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 1-8 of 8 results.

A132195 Number of three-prime Carmichael numbers less than 10^n.

Original entry on oeis.org

1, 7, 12, 23, 47, 84, 172, 335, 590, 1000, 1858, 3284, 6083, 10816, 19539, 35586, 65309, 120625, 224763, 420658, 790885, 1494738
Offset: 3

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Author

Jonathan Vos Post, Nov 19 2007

Keywords

Comments

a(n) = C_3(n) in Table 1, p. 34 of Chick (2007-2008) = card{c such that c is in A002997 INTERSECTION A014612 and c <= 10^n}.

References

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.
		

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.

Extensions

a(22) from Claude Goutier added by Amiram Eldar, Apr 19 2024
Showing 1-8 of 8 results.