cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 10 results.

A299710 Number of ten-prime Carmichael numbers less than 10^n.

Original entry on oeis.org

23, 340, 3058, 20738, 114232, 547528, 2347828
Offset: 16

Views

Author

Tim Johannes Ohrtmann, Feb 17 2018

Keywords

References

  • Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 220.

Links

Crossrefs

For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711.
Cf. A002997, A006931, A055553.

Extensions

a(22) from Claude Goutier added by Amiram Eldar, Apr 19 2024

A174613 Number of five-prime Carmichael numbers less than 10^n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 3, 27, 146, 492, 1336, 3156, 7082, 14938, 29282, 55012, 100707, 178063, 306310, 514381, 846627, 1370257
Offset: 0

Views

Author

Michel Lagneau, Mar 23 2010

Keywords

Examples

			For n=6, the smallest Carmichael number with 5 prime factors is 825265 = 5*7*17*19*73.

References

  • Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 220.

Links

Crossrefs

For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711.
Cf. A002997, A006931, A055553.

Extensions

a(22) from Claude Goutier added by Amiram Eldar, Apr 19 2024

A174612 Number of four-prime Carmichael numbers less than 10^n.

Original entry on oeis.org

0, 0, 0, 0, 0, 4, 19, 55, 144, 314, 619, 1179, 2102, 3639, 6042, 9938, 16202, 25758, 40685, 63343, 98253, 151566, 232742
Offset: 0

Views

Author

Michel Lagneau, Mar 23 2010

Keywords

Examples

			For n=5, the smallest Carmichael number with 4 prime factors is 41041 = 7*11*13*41.

References

  • Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 220.

Links

Crossrefs

For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711.
Cf. A002997, A006931, A055553.

Extensions

a(0) inserted and a(22) from Claude Goutier added by Amiram Eldar, Apr 19 2024

A174614 Number of six-prime Carmichael numbers less than 10^n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 14, 99, 459, 1714, 5270, 14401, 36907, 86696, 194306, 414660, 849564, 1681744, 3230120, 6034046
Offset: 0

Views

Author

Michel Lagneau, Mar 23 2010

Keywords

Examples

			For n=9: the smallest Carmichael number with 6 prime factors is 321197185 = 5*19*23*29*37*137.

References

  • Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 220.

Links

Crossrefs

For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711.
Cf. A002997, A006931, A055553.

Extensions

a(22) from Claude Goutier added by Amiram Eldar, Apr 19 2024

A174615 Number of seven-prime Carmichael numbers less than 10^n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 41, 262, 1340, 5359, 19210, 60150, 172234, 460553, 1159167, 2774702, 6363475, 14056367
Offset: 0

Views

Author

Michel Lagneau, Mar 23 2010

Keywords

Examples

			The smallest Carmichael number with 7 prime factors is 5394826801 = 7*13*17*23*31*67*73, and there is one other 10-digit example, so a(10)=2.

References

  • Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 220.

Links

Crossrefs

For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711.
Cf. A002997, A006931, A055553.

Extensions

a(22) from Claude Goutier added by Amiram Eldar, Apr 19 2024

A174616 Number of eight-prime Carmichael numbers less than 10^n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 89, 655, 3622, 16348, 63635, 223997, 720406, 2148017, 6015901, 16005646
Offset: 0

Views

Author

Michel Lagneau, Mar 23 2010

Keywords

Examples

			The smallest Carmichael number with 8 prime factors is 232250619601 = 7*11*13*17*31*37*73*163, and there are 6 others, so a(12) = 7.

References

  • Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 220.

Links

Crossrefs

For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711.
Cf. A002997, A006931, A055553.

Extensions

a(22) from Claude Goutier added by Amiram Eldar, Apr 19 2024

A174617 Number of nine-prime Carmichael numbers less than 10^n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 27, 170, 1436, 8835, 44993, 196391, 762963, 2714473, 8939435
Offset: 0

Views

Author

Michel Lagneau, Mar 23 2010

Keywords

Examples

			The smallest Carmichael number with 9 prime factors is 9746347772161 = 7*11*13*17*19*31*37*41*641, so a(13)=1..

References

  • Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 220.

Links

Crossrefs

For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711.
Cf. A002997, A006931, A055553.

Extensions

a(22) from Claude Goutier added by Amiram Eldar, Apr 19 2024

A299711 Number of eleven-prime Carmichael numbers less than 10^n.

Original entry on oeis.org

1, 49, 576, 5804, 42764, 262818
Offset: 17

Views

Author

Tim Johannes Ohrtmann, Feb 17 2018

Keywords

Examples

			60977817398996785 = 5*7*17*19*23*37*53*73*79*89*233 is the only Carmichael number with eleven prime factors below 10^17, so a(17) = 1.

Links

Crossrefs

For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711.
Cf. A002997, A006931, A055553.

Extensions

a(22) from Claude Goutier added by Amiram Eldar, Apr 19 2024

A036060 Number of 3-component Carmichael numbers C = (6M + 1)(12M + 1)(18M + 1) < 10^n.

Original entry on oeis.org

0, 1, 1, 2, 2, 3, 7, 10, 16, 25, 50, 86, 150, 256, 436, 783, 1435, 2631, 4765, 8766, 16320, 30601, 57719, 109504, 208822, 400643, 771735, 1494772, 2903761, 5658670, 11059937, 21696205, 42670184, 84144873, 66369603, 329733896, 655014986, 1303918824, 2601139051
Offset: 3

Views

Author

N. J. A. Sloane

Keywords

Comments

Note that this is different from the count of 3-Carmichael numbers, A132195. The numbers counted here are neither those listed in A087788 (3 arbitrary prime factors) nor those listed in A033502 (where 6m + 1, 12m + 1 and 18m + 1 are all prime). - M. F. Hasler, Apr 14 2015

References

  • Posting by Harvey Dubner (harvey(AT)dubner.com) to Number Theory List (NMBRTHRY(AT)LISTSERV.NODAK.EDU), Nov 23 1998.

Links

Crossrefs

Cf. A002997, A033502, A055553, A087788, A132195.

Extensions

Terms updated (from Dubner's paper) by Amiram Eldar, Aug 11 2017

A328937 The number of imprimitive 3-Carmichael numbers (A087788 and A328935) below 10^n.

Original entry on oeis.org

4, 11, 25, 59, 127, 252, 471, 928, 1734, 3462, 6615, 12725, 24396, 46877, 89854, 173331, 334737, 647265, 1253176
Offset: 6

Views

Author

Amiram Eldar, Oct 31 2019

Keywords

Comments

Granville and Pomerance conjectured that most Carmichael numbers are imprimitive, i.e. lim_{n->oo} a(n)/A132195(n) = 1.

Examples

			a(6) = 4 since there are 4 imprimitive 3-Carmichael numbers below 10^6: 294409, 399001, 488881, 512461.

Links

Crossrefs

Cf. A002997, A087788, A132195, A328935.
Showing 1-10 of 10 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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