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

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

Author

Michel Lagneau, Mar 23 2010

Keywords

• nonn
• more

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

• 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.

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