500 (number)

500 (five hundred) is the natural number following 499 and preceding 501.

← 499 500 501 →
List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	five hundred
Ordinal	500th (five hundredth)
Factorization	2^2 × 5^3
Greek numeral	Φ´
Roman numeral	D
Binary	1111101002
Ternary	2001123
Octal	7648
Duodecimal	35812
Hexadecimal	1F416

Mathematical properties

500 = 2² × 5³. It is a Harshad number in bases 5, 6, 10, 11, 13, 15 and 16.

Other fields

Five hundred is also

• the number that many NASCAR races often use at the end of their race names (e.g., Daytona 500), to denote the length of the race (in miles, kilometers or laps).
• the longest advertised distance (in miles) of the IndyCar Series and its premier race, the Indianapolis 500.

Slang names

• Monkey (UK slang for £500; USA slang for $500)[1]

Integers from 501 to 599

501

501 = 3 × 167. It is:

• the sum of the first 18 primes (a term of the sequence OEIS: A007504).
• palindromic in bases 9 (616₉) and 20 (151₂₀).

502

• 502 = 2 × 251

503

503 is:

• a prime number.
• a safe prime.[2]
• the sum of three consecutive primes (163 + 167 + 173).[3]
• the sum of the cubes of the first four primes.[4]
• a Chen prime[5]
• an Eisenstein prime with no imaginary part.[6]

504

504 = 2³ × 3² × 7. It is:

• a tribonacci number.[7]
• a semi-meandric number.
• a refactorable number.[8]
• a Harshad number in bases 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, and 16

505

• 505 = 5 × 101, Harshad number in bases 3, 5, and 6
• model number of Levi's jeans, model number of U-505
• This number is the magic constant of n×n normal magic square and n-queens problem for n = 10.

506

506 = 2 × 11 × 23. It is:

• a sphenic number.
• a square pyramidal number.[9]
• a pronic number.[10]
• a Harshad number in bases 4, 10, and 12

507

• 507 = 3 × 13², Harshad number in bases 13 and 14.

508

• 508 = 2² × 127, sum of four consecutive primes (113 + 127 + 131 + 137), Harshad number in base 13.

509

509 is:

• a prime number.
• a Sophie Germain prime, smallest Sophie Germain prime to start a 4-term Cunningham chain of the first kind {509, 1019, 2039, 4079}.
• a Chen prime.
• an Eisenstein prime with no imaginary part.
• a highly cototient number[11]

510

510 = 2 × 3 × 5 × 17. It is:

• the sum of eight consecutive primes (47 + 53 + 59 + 61 + 67 + 71 + 73 + 79).
• the sum of ten consecutive primes (31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71).
• the sum of twelve consecutive primes (19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67).
• a nontotient.
• a sparsely totient number.[12]
• a Harshad number in bases 3, 5, 6, 10, 11, 12, 13, 15, and 16

511

511 = 7 × 73. It is:

• a Harshad number in bases 3, 5, 7, 10, 13, and 15.
• a palindromic number and a repdigit in bases 2 (111111111₂) and 8 (777₈)
• 5-1-1, a roadway status and transit information hotline in many metropolitan areas of the United States.

512

512 = 2⁹. It is:

• a power of two.
• a cube of 8.
• a Leyland number.
• a Dudeney number.[13]
• a Harshad number in bases 2, 3, 4, 5, 7, 8, 9, 10, 13, 15, and 16.
• palindromic in bases 7 (1331₇) and 15 (242₁₅).

513

513 = 3³ × 19. It is:

• palindromic in bases 2 (1000000001₂) and 8 (1001₈)
• a Harshad number in bases 3, 4, 5, 7, 9, 10, 13, 14, 15, and 16
• Area code of Cincinnati, Ohio

514

514 = 2 × 257, it is:

• a centered triangular number.[14]
• a nontotient
• a palindromic in bases 4 (20002₄), 16 (202₁₆), and 19 (181₁₉)
• a Harshad number in base 2.
• a Area Code for Montreal Canada

515

515 = 5 × 103, it is:

• the sum of nine consecutive primes (41 + 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73).
• a Harshad number in bases 3, 4, and 16.

516

516 = 2² × 3 × 43, it is:

• nontotient.
• untouchable number.[15]
• refactorable number.[8]
• a Harshad number in bases 2, 3, 4, 6, 7, 9, 10, 13, 15, and 16.

517

517 = 11 × 47, it is:

• the sum of five consecutive primes (97 + 101 + 103 + 107 + 109).
• a Smith number.[16]
• a Harshad number in base 12.

518

518 = 2 × 7 × 37, it is:

• = 5¹ + 1² + 8³ (a property shared with 175 and 598).
• a sphenic number.
• a nontotient.
• an untouchable number.[15]
• palindromic and a repdigit in bases 6 (2222₆) and 36 (EE₃₆).
• a Harshad number in bases 8, 9, 10, 13, and 15.

519

519 = 3 × 173, it is:

• the sum of three consecutive primes (167 + 173 + 179)
• palindromic in bases 9 (636₉) and 12 (373₁₂).

520

520 = 2³ × 5 × 13. It is:

• an untouchable number.[15]
• a palindromic number in base 14 (292₁₄).
• a Harshad number in bases 2, 4, 5, 6, 7, 8, 11, 13, 14, and 16.

521

521 is:

• a Lucas prime.[17]
• A Mersenne exponent, i.e. 2⁵²¹−1 is prime.
• a Chen prime.
• an Eisenstein prime with no imaginary part.
• palindromic in bases 11 (434₁₁) and 20 (161₂₀)

522

522 = 2 × 3² × 29. It is:

• the sum of six consecutive primes (73 + 79 + 83 + 89 + 97 + 101).
• a repdigit in bases 28 (II₂₈) and 57 (99₅₇).
• a Harshad number in bases 2, 4, 10, 13, and 15.

523

523 is:

• a prime number.
• the sum of seven consecutive primes (61 + 67 + 71 + 73 + 79 + 83 + 89).
• palindromic in bases 13 (313₁₃) and 18 (1B1₁₈).

524

524 = 2² × 131

525

525 = 3 × 5² × 7. It is:

• palindromic in base 10 (525₁₀).
• a Harshad number in bases 3, 5, 8, 11, 15, and 16.
• the number of scan lines in the NTSC television standard.
• a self number.

526

526 = 2 × 263, centered pentagonal number,[18] nontotient, Smith number[16]

527

527 = 17 × 31. it is:

• palindromic in base 15 (252₁₅).
• a Harshad number in bases 11 and 16.
• also, the section of the US Tax Code regulating soft money political campaigning (see 527 groups)

528

528 = 2⁴ × 3 × 11. It is:

• a triangular number.
• palindromic in bases 9 (646₉) and 17 (1E1₁₇).
• a Harshad number in bases 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, and 16.

529

529 = 23². It is:

• a centered octagonal number.[19]
• also Section 529 of the IRS tax code organizes 529 plans to encourage saving for higher education.

530

530 = 2 × 5 × 53. It is:

• a sphenic number.
• a nontotient.
• the sum of totient function for first 41 integers.
• an untouchable number.[15]
• the sum of the first three perfect numbers.
• palindromic in bases 4 (20102₄), 16 (212₁₆), and 23 (101₂₃).
• a Harshad number in bases 4, 6, 8, 11, and 16.
• a US telophone area code that covers much of Northern California.

531

531 = 3² × 59. It is:

• palindromic in base 12 (383₁₂).
• a Harshad number in base 10.

532

532 = 2² × 7 × 19. It is:

• a pentagonal number.[20]
• a nontotient.
• palindromic and a repdigit in bases 11 (444₁₁), 27 (JJ₂₇), and 37 (EE₃₇).
• a Harshad number in bases 4, 8, 15, and 16.

533

533 = 13 × 41. It is:

• the sum of three consecutive primes (173 + 179 + 181).
• the sum of five consecutive primes (101 + 103 + 107 + 109 + 113).
• palindromic in base 19 (191₁₉).
• a Harshad number in bases 6, 9, 11, and 14.

534

534 = 2 × 3 × 89. It is:

• a sphenic number.
• the sum of four consecutive primes (127 + 131 + 137 + 139).
• a nontotient.
• palindromic in bases 5 (4114₅) and 14 (2A2₁₄).
• a Harshad number in bases 3, 4, and 13.

535

535 = 5 × 107. It is:

• a Smith number.[16]
• a Harshad number in base 2.

${\displaystyle 34n^{3}+51n^{2}+27n+5}$ for ${\displaystyle n=2}$; this polynomial plays an essential role in Apéry's proof that ${\displaystyle \zeta (3)}$ is irrational.

535 is used as an abbreviation for May 35, which is used in China instead of June 4 to evade censorship by the Chinese government of references on the Internet to the Tiananmen Square protests of 1989.[21]

536

536 = 2³ × 67. It is:

• the number of ways to arrange the pieces of the ostomachion into a square, not counting rotation or reflection.
• a refactorable number.[8]
• the lowest happy number beginning with the digit 5.
• a Harshad number in bases 3, 5, 8, and 13.

537

537 = 3 × 179, Mertens function (537) = 0

538

538 = 2 × 269. It is:

• an open meandric number.
• a nontotient.
• the total number of votes in the United States Electoral College.
  • the website FiveThirtyEight.
• Radio 538, a Dutch commercial radio station

539

539 = 7² × 11

540

540 = 2² × 3³ × 5. It is:

• an untouchable number.[15]
• a decagonal number.[22]
• a repdigit in bases 26 (KK₂₆), 29 (II₂₉), 35 (FF₃₅), 44 (CC₄₄), 53 (AA₅₃), and 59 (99₅₉).
• a Harshad number in bases 2, 3, 4, 6, 7, 9, 10, 11, 12, 13, 14, and 16.

541

541 is:

• the 100th prime.
• a lucky prime.[23]
• a Chen prime.
• the 10th star number.[24]
• palindromic in bases 18 (1C1₁₈) and 20 (171₂₀).

Mertens function(541) = 0.

542

542 = 2 × 271. It is:

• a nontotient.
• the sum of totient function for the first 42 integers.

543

543 = 3 × 181; palindromic in bases 11 (454₁₁) and 12 (393₁₂).

544

544 = 2⁵ × 17. It is:

• a Harshad number in bases 2, 4, 9, 12, 13, and 16.

545

545 = 5 × 109. It is:

• a centered square number.[25]
• palindromic in bases 10 (545₁₀) and 17 (1F1₁₇).
• a Harshad number in bases 4 and 16.

546

546 = 2 × 3 × 7 × 13. It is:

• the sum of eight consecutive primes (53 + 59 + 61 + 67 + 71 + 73 + 79 + 83).
• palindromic in bases 4 (20202₄), 9 (666₉), and 16 (222₁₆).
• a repdigit in bases 9 and 16.
• a Harshad number in bases 2, 3, 4, 6, 7, 8, 13, 14, 15, and 16.

547

547 is:

• a prime number.
• a cuban prime.[26]
• a centered hexagonal number.[27]
• a centered heptagonal number.[28]

548

548 = 2² × 137. It is:

• a nontotient.
• the default port for the Apple Filing Protocol.

Also, every positive integer is the sum of at most 548 ninth powers;

549

549 = 3² × 61, It is:

• a repdigit in bases 13 (333₁₃) and 60 (99₆₀).
• a Harshad number in bases 6, 7, 13, and 16.

550

550 = 2 × 5² × 11. It is:

• a pentagonal pyramidal number.[29]
• a primitive abundant number.[30]
• a nontotient.
• a repdigit in bases 24 (MM₂₄), 49 (BB₄₉), and 54 (AA₅₄).
• a Harshad number in bases 6, 7, 8, 10, 11, 12, 13, and 16.
• the SMTP status code meaning the requested action was not taken because the mailbox is unavailable

551

551 = 19 × 29. It is:

• the sum of three consecutive primes (179 + 181 + 191).
• palindromic in base 22 (131₂₂).
• a Harshad number in base 15.
• the SMTP status code meaning user is not local

552

552 = 2³ × 3 × 23. It is:

• the sum of six consecutive primes (79 + 83 + 89 + 97 + 101 + 103).
• the sum of ten consecutive primes (37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73).
• a pronic number.[10]
• an untouchable number.[15]
• palindromic in base 19 (1A1₁₉).
• a Harshad number in bases 2, 3, 4, 5, 7, 8, 10, 11, 13, and 16.
• the model number of U-552.
• the SMTP status code meaning requested action aborted because the mailbox is full.

553

553 = 7 × 79. It is:

• the sum of nine consecutive primes (43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79).
• a Harshad number in bases 3, 4, 7, and 8.
• the model number of U-553
• the SMTP status code meaning requested action aborted because of faulty mailbox name.

554

554 = 2 × 277. It is:

• a nontotient.
• the SMTP status code meaning transaction failed.

Mertens function(554) = 6, a record high that stands until 586.

555

555 = 3 × 5 × 37 is:

• a sphenic number.
• palindromic in bases 9 (676₉), 10 (555₁₀), and 12 (3A3₁₂).
• a repdigit in bases 10 and 36.
• a Harshad number in bases 2, 10, 11, 13, and 16.
• The telephone exchange for fictitious phone numbers in US movies – see 5-5-5
• The number of keyboard sonatas written by Domenico Scarlatti, according to the catalog by Ralph Kirkpatrick.
• the model number of the 555 timer IC, a classic integrated circuit (chip) implementing a variety of timer and multivibrator applications, and historically widely used in electronics.
• The number of seats of the airliner A380-800.
• The tokusatsu series Kamen Rider 555 (read as Kamen Rider Faiz).

556

556 = 2² × 139. It is:

• the sum of four consecutive primes (131 + 137 + 139 + 149).
• an untouchable number, because it is never the sum of the proper divisors of any integer.[15]
• a happy number.
• a Harshad number in base 2.
• the model number of U-556; 5.56×45mm NATO cartridge.

557

557 is:

• a prime number.
• a Chen prime.
• an Eisenstein prime with no imaginary part.

558

558 = 2 × 3² × 31. It is:

• a nontotient.
• a repdigit in bases 30 (II₃₀) and 61 (99₆₁).
• a Harshad number in bases 3, 4, 10, 11, 13, and 16.
• The sum of the largest prime factors of the first 558 is itself divisible by 558 (the previous such number is 62, the next is 993).
• in the title of the Star Trek: Deep Space Nine episode "The Siege of AR-558"

559

559 = 13 × 43. It is:

• the sum of five consecutive primes (103 + 107 + 109 + 113 + 127).
• the sum of seven consecutive primes (67 + 71 + 73 + 79 + 83 + 89 + 97).
• a nonagonal number.[31]
• a centered cube number.[32]
• palindromic in base 18 (1D1₁₈).
• a Harshad number in bases 7, 8, and 15
• the model number of U-559.

560

560 = 2⁴ × 5 × 7. It is:

• a tetrahedral number.[33]
• a refactorable number.
• palindromic in bases 3 (202202₃) and 6 (2332₆).
• a Harshad number in bases 3, 4, 5, 6, 7, 8, 9, 11, 13, 14, 15, and 16.

561

561 = 3 × 11 × 17. It is:

• a triangular number.
• a hexagonal number.[34]
• palindromic in bases 2 (1000110001₂) and 20 (181₂₀).
• a Harshad number in bases 6, 9, and 11.
• the first Carmichael number[35]

562

562 = 2 × 281. It is:

• a Smith number.[16]
• an untouchable number.[15]
• the sum of twelve consecutive primes (23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71).
• palindromic in bases 4 (20302₄), 13 (343₁₃), 14 (2C2₁₄), 16 (232₁₆), and 17 (1G1₁₇).
• the number of Native American (including Alaskan) Nations, or "Tribes," recognized by the USA government.

563

563 is:

• a prime number.
• a safe prime.[2]
• the largest known Wilson prime.[36]
• a Chen prime.
• an Eisenstein prime with no imaginary part.
• a balanced prime.[37]
• a strictly non-palindromic number.[38]
• a sexy prime.
• a happy prime.

564

564 = 2² × 3 × 47. It is:

• the sum of a twin prime (281 + 283).
• a refactorable number.
• palindromic in bases 5 (4224₅) and 9 (686₉).
• a Harshad number in bases 2, 4, 5, 7, and 13.

565

565 = 5 × 113. It is:

• the sum of three consecutive primes (181 + 191 + 193).
• a member of the Mian–Chowla sequence.[39]
• a happy number.
• palindromic in bases 10 (565₁₀) and 11 (474₁₁).
• a Harshad number in base 2.

566

566 = 2 × 283. It is:

• nontotient.
• a happy number.

567

567 = 3⁴ × 7. It is:

• palindromic in base 12 (3B3₁₂).
• a Harshad number in bases 3, 4, 7, 9, 14, and 15.

568

568 = 2³ × 71. It is:

• the sum of the first nineteen primes (a term of the sequence OEIS: A007504).
• a refactorable number.
• palindromic in bases 7 (1441₇) and 21 (161₂₁).
• a Harshad number in bases 2, 3, 8, and 9.
• the smallest number whose seventh power is the sum of 7 seventh powers.
• the room number booked by Benjamin Braddock in the 1967 film The Graduate.
• the number of millilitres in an imperial pint.
• the name of the Student Union bar at Imperial College London

569

569 is:

• a prime number.
• a Chen prime.
• an Eisenstein prime with no imaginary part.
• a strictly non-palindromic number.[38]

570

570 = 2 × 3 × 5 × 19. It is:

• a Harshad number in bases 2, 5, 6, 8, 9, 15, and 16.

571

571 is:

• a prime number.
• a Chen prime.
• a centered triangular number.[14]
• the model number of U-571 which appeared in the 2000 movie U-571

572

572 = 2² × 11 × 13. It is:

• a primitive abundant number.[30]
• a nontotient.
• palindromic in bases 3 (210012₃) and 15 (282₁₅).
• a Harshad number in bases 12 and 14.

573

573 = 3 × 191. It is:

• known as the Konami number, because Konami can be represented by 573's Goroawase form of "ko-na-mi".
• the model number of German submarine U-573.

574

574 = 2 × 7 × 41. It is:

• a sphenic number.
• a nontotient.
• palindromic in base 9 (707₉).
• a Harshad number in bases 5, 6, 8, 9, 11, and 15.

575

575 = 5² × 23. It is:

• palindromic in bases 10 (575₁₀) and 13 (353₁₃).
• a Harshad number in base 12.

576

576 = 2⁶ × 3² = 24². It is:

• the sum of four consecutive primes (137 + 139 + 149 + 151).
• a highly totient number.[40]
• a Smith number.[16]
• an untouchable number.[15]
• palindromic in bases 11 (484₁₁), 14 (2D2₁₄), and 23 (121₂₃).
• a Harshad number in bases 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, and 16.
• four-dozen sets of a dozen, which makes it 4 gross.

577

577 is:

• a prime number.
• a Proth prime.[41]
• palindromic in bases 18 (1E1₁₈) and 24 (101₂₄).
• the number of seats in National Assembly (France).

578

578 = 2 × 17². It is:

• a nontotient.
• palindromic in base 16 (242₁₆).

579

579 = 3 × 193; it is a ménage number.[42]

580

580 = 2² × 5 × 29. It is:

• the sum of six consecutive primes (83 + 89 + 97 + 101 + 103 + 107).
• palindromic in bases 12 (404₁₂) and 17 (202₁₇).
• a Harshad number in bases 4, 6, 11, 15, and 16.

581

581 = 7 × 83. It is:

• the sum of three consecutive primes (191 + 193 + 197).
• a Harshad number in bases 3 and 8.

582

582 = 2 × 3 × 97. It is:

• a sphenic number.
• the sum of eight consecutive primes (59 + 61 + 67 + 71 + 73 + 79 + 83 + 89).
• a nontotient.
• a Harshad number in bases 3 and 4.

583

583 = 11 × 53. It is:

• palindromic in base 9 (717₉).
• a Harshad number in bases 5 and 12.

584

584 = 2³ × 73. It is:

• an untouchable number.[15]
• the sum of totient function for first 43 integers.
• a refactorable number.
• a Harshad number in base 3.

585

585 = 3² × 5 × 13. It is:

• palindromic in bases 2 (1001001001₂), 8 (1111₈), and 10 (585₁₀).
• a repdigit in bases 8, 38, 44, and 64.
• the sum of powers of 8 from 0 to 3.
• a Harshad number in bases 3, 5, 7, 9, 11, 12, 13, and 16.

When counting in binary with fingers, expressing 585 as 1001001001, results in the isolation of the index and little fingers of each hand, "throwing up the horns".

586

586 = 2 × 293.

• Mertens function(586) = 7 a record high that stands until 1357.
• it is the number of several popular personal computer processors (such as the Intel pentium).

587

587 is:

• a prime number.
• safe prime.[2]
• a Chen prime.
• an Eisenstein prime with no imaginary part.
• the sum of five consecutive primes (107 + 109 + 113 + 127 + 131).
• palindromic in bases 11 (494₁₁) and 15 (292₁₅).
• the outgoing port for email message submission.

588

588 = 2² × 3 × 7². It is:

• a Smith number.[16]
• palindromic in base 13 (363₁₃).
• a Harshad number in bases 2, 3, 4, 5, 7, 8, 9, 10, 13, 14, and 15.

589

589 = 19 × 31. It is:

• the sum of three consecutive primes (193 + 197 + 199).
• palindromic in base 21 (171₂₁).
• a Harshad number in bases 11 and 16.

590

590 = 2 × 5 × 59. It is:

• a sphenic number.
• a pentagonal number.[20]
• a nontotient.
• palindromic in base 19 (1C1₁₉).
• a Harshad number in bases 2, 5, 6, and 14.

591

591 = 3 × 197

592

592 = 2⁴ × 37. It is:

• palindromic in bases 9 (727₉) and 12 (414₁₂).
• a Harshad number in bases 3, 4, 8, 9, 10, and 13.

593

593 is:

• a prime number.
• a Sophie Germain prime.
• the sum of seven consecutive primes (71 + 73 + 79 + 83 + 89 + 97 + 101).
• the sum of nine consecutive primes (47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83).
• an Eisenstein prime with no imaginary part.
• a balanced prime.[37]
• a Leyland prime.
• a member of the Mian–Chowla sequence.[39]
• strictly non-palindromic prime.[38]

594

594 = 2 × 3³ × 11. It is:

• the sum of ten consecutive primes (41 + 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79).
• a nontotient.
• palindromic in bases 5 (4334₅) and 16 (252₁₆).
• a Harshad number in bases 4, 6, 8, 10, 12, 13, 1,4 and 16.

595

595 = 5 × 7 × 17. It is:

• a sphenic number.
• a triangular number.
• centered nonagonal number.[43]
• palindromic in bases 10 (595₁₀) and 18 (1F1₁₈).
• a Harshad number in bases 2, 3, 4, 7, and 8.

596

596 = 2² × 149. It is:

• the sum of four consecutive primes (139 + 149 + 151 + 157).
• a nontotient.
• a Harshad number in base 2.

597

597 = 3 × 199

598

598 = 2 × 13 × 23 = 5¹ + 9² + 8³. It is:

• a sphenic number.
• palindromic in bases 4 (21112₄) and 11 (4A4₁₁).
• a Harshad number in bases 6, 14, and 16.

599

599 is:

• a prime number.
• a Chen prime.
• an Eisenstein prime with no imaginary part.

References

1. Evans, I.H., Brewer's Dictionary of Phrase and Fable, 14th ed., Cassell, 1990, ISBN 0-304-34004-9
2. Sloane, N. J. A. (ed.). "Sequence A005385 (Safe primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
3. that is, a term of the sequence OEIS: A034961
4. that is, the first term of the sequence OEIS: A133525
5. since 503+2 is a product of two primes, 5 and 101
6. since it is a prime which is congruent to 2 modulo 3.
7. Sloane, N. J. A. (ed.). "Sequence A000073 (Tribonacci numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
8. Sloane, N. J. A. (ed.). "Sequence A033950 (Refactorable numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
9. Sloane, N. J. A. (ed.). "Sequence A000330 (Square pyramidal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
10. Sloane, N. J. A. (ed.). "Sequence A002378 (Oblong (or promic, pronic, or heteromecic) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
11. Sloane, N. J. A. (ed.). "Sequence A100827 (Highly cototient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
12. Sloane, N. J. A. (ed.). "Sequence A036913 (Sparsely totient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
13. Sloane, N. J. A. (ed.). "Sequence A061209 (Numbers which are the cubes of their digit sum)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
14. Sloane, N. J. A. (ed.). "Sequence A005448 (Centered triangular numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
15. Sloane, N. J. A. (ed.). "Sequence A005114 (Untouchable numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
16. Sloane, N. J. A. (ed.). "Sequence A006753 (Smith numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
17. Sloane, N. J. A. (ed.). "Sequence A005479 (Prime Lucas numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
18. Sloane, N. J. A. (ed.). "Sequence A005891 (Centered pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
19. Sloane, N. J. A. (ed.). "Sequence A016754 (Odd squares: a(n) = (2n+1)^2. Also centered octagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
20. Sloane, N. J. A. (ed.). "Sequence A000326 (Pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
21. Larmer, Brook (October 26, 2011). "Where an Internet Joke Is Not Just a Joke". New York Times. Retrieved November 1, 2011.
22. Sloane, N. J. A. (ed.). "Sequence A001107 (10-gonal (or decagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
23. Sloane, N. J. A. (ed.). "Sequence A031157 (Numbers that are both lucky and prime)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
24. Sloane, N. J. A. (ed.). "Sequence A003154 (Centered 12-gonal numbers. Also star numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
25. Sloane, N. J. A. (ed.). "Sequence A001844 (Centered square numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
26. Sloane, N. J. A. (ed.). "Sequence A002407 (Cuban primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
27. Sloane, N. J. A. (ed.). "Sequence A003215 (Hex (or centered hexagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
28. Sloane, N. J. A. (ed.). "Sequence A069099 (Centered heptagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
29. Sloane, N. J. A. (ed.). "Sequence A002411 (Pentagonal pyramidal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
30. Sloane, N. J. A. (ed.). "Sequence A071395 (Primitive abundant numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
31. Sloane, N. J. A. (ed.). "Sequence A001106 (9-gonal (or enneagonal or nonagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
32. Sloane, N. J. A. (ed.). "Sequence A005898 (Centered cube numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
33. Sloane, N. J. A. (ed.). "Sequence A000292 (Tetrahedral numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
34. Sloane, N. J. A. (ed.). "Sequence A000384 (Hexagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
35. Higgins, Peter (2008). Number Story: From Counting to Cryptography. New York: Copernicus. p. 14. ISBN 978-1-84800-000-1.
36. Sloane, N. J. A. (ed.). "Sequence A007540 (Wilson primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
37. Sloane, N. J. A. (ed.). "Sequence A006562 (Balanced primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
38. Sloane, N. J. A. (ed.). "Sequence A016038 (Strictly non-palindromic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
39. Sloane, N. J. A. (ed.). "Sequence A005282 (Mian-Chowla sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
40. Sloane, N. J. A. (ed.). "Sequence A097942 (Highly totient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
41. Sloane, N. J. A. (ed.). "Sequence A080076 (Proth primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
42. Sloane, N. J. A. (ed.). "Sequence A000179 (Ménage numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
43. Sloane, N. J. A. (ed.). "Sequence A060544 (Centered 9-gonal (also known as nonagonal or enneagonal) numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.