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.
%I A174612 #26 Apr 22 2025 10:48:46 %S A174612 0,0,0,0,0,4,19,55,144,314,619,1179,2102,3639,6042,9938,16202,25758, %T A174612 40685,63343,98253,151566,232742 %N A174612 Number of four-prime Carmichael numbers less than 10^n. %D A174612 Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 220. %H A174612 Claude Goutier, <a href="http://www-labs.iro.umontreal.ca/~goutier/OEIS/A055553/">Text file readme.text summarizing enumeration of Carmichael numbers up to 10^22</a>. %H A174612 Claude Goutier, <a href="/A055553/a055553.txt">Text file readme.text summarizing enumeration of Carmichael numbers up to 10^22</a>. [Local copy, with permission] %H A174612 R. G. E. Pinch, <a href="http://s369624816.websitehome.co.uk/rgep/p82p.pdf">The Carmichael numbers up to 10^21</a>, Proceedings of Conference on Algorithmic Number Theory 2007. %e A174612 For n=5, the smallest Carmichael number with 4 prime factors is 41041 = 7*11*13*41. %Y A174612 For k-prime Carmichael numbers up to 10^n for k = 3,4,...,11, see A132195, A174612, A174613, A174614, A174615, A174616, A174617, A299710, A299711. %Y A174612 Cf. A002997, A006931, A055553. %K A174612 nonn,more %O A174612 0,6 %A A174612 _Michel Lagneau_, Mar 23 2010 %E A174612 a(0) inserted and a(22) from _Claude Goutier_ added by _Amiram Eldar_, Apr 19 2024