500 (number)
500 (five hundred) is the natural number following 499 and preceding 501.
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Look up five hundred in Wiktionary, the free dictionary. |
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Cardinal | five hundred | |||
Ordinal | 500th (five hundredth) | |||
Factorization | 22 × 53 | |||
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, meaning divisible by the sum of its digits.
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:
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.
505
- 505 = 5 × 101
- 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.
507
- 507 = 3 × 132
508
- 508 = 22 × 127, sum of four consecutive primes (113 + 127 + 131 + 137).
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.
511
511 = 7 × 73. It is:
- a Harshad number.
- 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 = 83 = 29. It is:
- a power of two.
- a cube of 8.
- a Leyland number.
- a Dudeney number.[13]
- a Harshad number.
- 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
- Area code of Cincinnati, Ohio
514
514 = 2 × 257, it is:
- a centered triangular number.[14]
- a nontotient
- a palindrome in bases 4 (200024), 16 (20216), and 19 (18119)
- an 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).
516
516 = 22 × 3 × 43, it is:
- nontotient.
- untouchable number.[15]
- refactorable number.[8]
- a Harshad number.
517
517 = 11 × 47, it is:
- the sum of five consecutive primes (97 + 101 + 103 + 107 + 109).
- a Smith number.[16]
518
518 = 2 × 7 × 37, it is:
519
519 = 3 × 173, it is:
- the sum of three consecutive primes (167 + 173 + 179)
- palindromic in bases 9 (6369) and 12 (37312).
521
521 is:
- a Lucas prime.[17]
- A Mersenne exponent, i.e. 2521−1 is prime.
- The largest known such exponent that is the lesser of twin primes[18]
- 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.
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).
- the number of scan lines in the NTSC television standard.
- a self number.
526
526 = 2 × 263, centered pentagonal number,[19] nontotient, Smith number[16]
527
527 = 17 × 31. it is:
- palindromic in base 15 (25215).
- also, the section of the US Tax Code regulating soft money political campaigning (see 527 groups)
529
529 = 232. It is:
- a centered octagonal number.[20]
- 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 US telephone area code that covers much of Northern California.
531
531 = 32 × 59. It is:
- palindromic in base 12 (38312).
- a Harshad number.
532
532 = 22 × 7 × 19. It is:
- a pentagonal number.[21]
- a nontotient.
- palindromic and a repdigit in bases 11 (44411), 27 (JJ27), and 37 (EE37).
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).
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).
535
535 = 5 × 107. It is:
- a Smith number.[16]
for ; this polynomial plays an essential role in Apéry's proof that 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.[22]
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.
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.[23]
- a repdigit in bases 26 (KK26), 29 (II29), 35 (FF35), 44 (CC44), 53 (AA53), and 59 (9959).
- a Harshad number.
- the number of doors to Valhalla according to the Prose Edda.[24]
- the number of floors in Thor's hall, known as Bilskirnir, according to the Prose Edda.[25]
541
541 is:
- the 100th prime.
- a lucky prime.[26]
- a Chen prime.
- the 10th star number.[27]
- palindromic in bases 18 (1C118) and 20 (17120).
Mertens function(541) = 0.
543
543 = 3 × 181; palindromic in bases 11 (45411) and 12 (39312).
544
544 = 25 × 17.
545
545 = 5 × 109. It is:
- a centered square number.[28]
- palindromic in bases 10 (54510) and 17 (1F117).
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.
547
547 is:
- a prime number.
- a cuban prime.[29]
- a centered hexagonal number.[30]
- a centered heptagonal number.[31]
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).
550
550 = 2 × 52 × 11. It is:
- a pentagonal pyramidal number.[32]
- a primitive abundant number.[33]
- a nontotient.
- a repdigit in bases 24 (MM24), 49 (BB49), and 54 (AA54).
- a Harshad number.
- the SMTP status code meaning the requested action was not taken because the mailbox is unavailable
551
551 = 19 × 29. It is:
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.
- 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).
- 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.
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.
- 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.
- 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.[35]
- a centered cube number.[36]
- palindromic in base 18 (1D118).
- the model number of U-559.
560
560 = 24 × 5 × 7. It is:
- a tetrahedral number.[37]
- a refactorable number.
- palindromic in bases 3 (2022023) and 6 (23326).
561
561 = 3 × 11 × 17. It is:
- a triangular number.
- a hexagonal number.[38]
- palindromic in bases 2 (10001100012) and 20 (18120).
- the first Carmichael number[39]
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.[40]
- a Chen prime.
- an Eisenstein prime with no imaginary part.
- a balanced prime.[41]
- a strictly non-palindromic number.[42]
- 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).
565
565 = 5 × 113. It is:
- the sum of three consecutive primes (181 + 191 + 193).
- a member of the Mian–Chowla sequence.[43]
- a happy number.
- palindromic in bases 10 (56510) and 11 (47411).
566
566 = 2 × 283. It is:
- nontotient.
- a happy number.
567
567 = 34 × 7. It is:
- palindromic in base 12 (3B312).
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).
- 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.[42]
570
570 = 2 × 3 × 5 × 19. It is:
571
571 is:
572
572 = 22 × 11 × 13. It is:
- a primitive abundant number.[33]
- a nontotient.
- palindromic in bases 3 (2100123) and 15 (28215).
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).
575
575 = 52 × 23. It is:
- palindromic in bases 10 (57510) and 13 (35313).
576
576 = 26 × 32 = 242. It is:
- the sum of four consecutive primes (137 + 139 + 149 + 151).
- a highly totient number.[44]
- a Smith number.[16]
- an untouchable number.[15]
- palindromic in bases 11 (48411), 14 (2D214), and 23 (12123).
- a Harshad number.
- four-dozen sets of a dozen, which makes it 4 gross.
577
577 is:
- a prime number.
- a Proth prime.[45]
- 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.[46]
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).
581
581 = 7 × 83. It is:
- the sum of three consecutive primes (191 + 193 + 197).
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.
583
583 = 11 × 53. It is:
- palindromic in base 9 (7179).
584
584 = 23 × 73. It is:
- an untouchable number.[15]
- the sum of totient function for first 43 integers.
- a refactorable number.
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.
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.
589
589 = 19 × 31. It is:
- the sum of three consecutive primes (193 + 197 + 199).
- palindromic in base 21 (17121).
590
590 = 2 × 5 × 59. It is:
- a sphenic number.
- a pentagonal number.[21]
- a nontotient.
- palindromic in base 19 (1C119).
591
591 = 3 × 197
592
592 = 24 × 37. It is:
- palindromic in bases 9 (7279) and 12 (41412).
- a Harshad number.
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.[41]
- a Leyland prime.
- a member of the Mian–Chowla sequence.[43]
- strictly non-palindromic prime.[42]
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.
595
595 = 5 × 7 × 17. It is:
- a sphenic number.
- a triangular number.
- centered nonagonal number.[47]
- palindromic in bases 10 (59510) and 18 (1F118).
596
596 = 22 × 149. It is:
- the sum of four consecutive primes (139 + 149 + 151 + 157).
- a nontotient.
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).
599
599 is:
- a prime number.
- a Chen prime.
- an Eisenstein prime with no imaginary part.
References
- Evans, I.H., Brewer's Dictionary of Phrase and Fable, 14th ed., Cassell, 1990, ISBN 0-304-34004-9
- Sloane, N. J. A. (ed.). "Sequence A005385 (Safe primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- that is, a term of the sequence OEIS: A034961
- that is, the first term of the sequence OEIS: A133525
- since 503+2 is a product of two primes, 5 and 101
- since it is a prime which is congruent to 2 modulo 3.
- Sloane, N. J. A. (ed.). "Sequence A000073 (Tribonacci numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A033950 (Refactorable numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A000330 (Square pyramidal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- 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.
- Sloane, N. J. A. (ed.). "Sequence A100827 (Highly cototient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A036913 (Sparsely totient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- 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.
- Sloane, N. J. A. (ed.). "Sequence A005448 (Centered triangular numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A005114 (Untouchable numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A006753 (Smith numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A005479 (Prime Lucas numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Dr. Kirkby (May 19, 2021). "Many more twin primes below Mersenne exponents than above Mersenne exponents". Mersenne Forum.
- Sloane, N. J. A. (ed.). "Sequence A005891 (Centered pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- 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.
- Sloane, N. J. A. (ed.). "Sequence A000326 (Pentagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Larmer, Brook (October 26, 2011). "Where an Internet Joke Is Not Just a Joke". New York Times. Retrieved November 1, 2011.
- 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.
- Snorri Sturluson. "Prose Edda". p. 107.
- Snorri Sturluson. "Prose Edda". p. 82.
- 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.
- 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.
- Sloane, N. J. A. (ed.). "Sequence A001844 (Centered square numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A002407 (Cuban primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- 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.
- Sloane, N. J. A. (ed.). "Sequence A069099 (Centered heptagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A002411 (Pentagonal pyramidal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A071395 (Primitive abundant numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- "Sloane's A000055: Number of trees with n unlabeled nodes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Archived from the original on 2010-11-29. Retrieved 2021-12-19.
- 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.
- Sloane, N. J. A. (ed.). "Sequence A005898 (Centered cube numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A000292 (Tetrahedral numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A000384 (Hexagonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Higgins, Peter (2008). Number Story: From Counting to Cryptography. New York: Copernicus. p. 14. ISBN 978-1-84800-000-1.
- Sloane, N. J. A. (ed.). "Sequence A007540 (Wilson primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A006562 (Balanced primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A016038 (Strictly non-palindromic numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A005282 (Mian-Chowla sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A097942 (Highly totient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A080076 (Proth primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- Sloane, N. J. A. (ed.). "Sequence A000179 (Ménage numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-11.
- 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.