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

0, 0, 0, 0, 0, 0, 1, 3, 27, 146, 492, 1336, 3156, 7082, 14938, 29282, 55012, 100707, 178063, 306310, 514381, 846627, 1370257, 2181324, 3429390

Offset

0,8

References

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

Links

Table of n, a(n) for n=0..24.

Claude Goutier, Text file readme.text summarizing enumeration of Carmichael numbers up to 10^22.

Claude Goutier, Text file readme.text summarizing enumeration of Carmichael numbers up to 10^22. [Local copy, with permission]

R. G. E. Pinch, The Carmichael numbers up to 10^21, Proceedings of Conference on Algorithmic Number Theory 2007.

Andrew Shallue and Jonathan Webster, Algorithms for Carmichael numbers, arXiv:2506.09903 [math.NT], 2025-2026.

Index entries for sequences related to Carmichael numbers.

Example

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

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.

Sequence in context: A080424 A285008 A001796 * A341566 A354655 A127509

Adjacent sequences: A174610 A174611 A174612 * A174614 A174615 A174616

Keyword

nonn,more

Author

Michel Lagneau, Mar 23 2010

Extensions

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

a(23)-a(24) from Shallue and Webster (2025-2026) added by Amiram Eldar, Jan 24 2026

Status

approved