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

1, 49, 576, 5804, 42764, 262818

Offset

17,2

Links

Table of n, a(n) for n=17..22.

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]

Richard Pinch, Tables relating to Carmichael numbers.

Example

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.

Cf. A002997, A006931, A055553.

Sequence in context: A110203 A263704 A166832 * A175775 A215117 A350982

Adjacent sequences: A299708 A299709 A299710 * A299712 A299713 A299714

Keyword

nonn,more,hard

Author

Tim Johannes Ohrtmann, Feb 17 2018

Extensions

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

Status

approved