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 A066858 #3 Oct 03 2012 17:57:02 %S A066858 2,3,3,5,3,7,3,7,5,11,0,13,7,5,5,17,0,19,0,7,11,23,0,21,13,19,0,29,5, %T A066858 31,9,11,17,13,0,37,19,13,0,41,7,43,0,0,23,47,0,43,0,17,0,53,0,21,0, %U A066858 19,29,59,0,61,31,0,17,13,11,67,0,23,13,71,0,73,37,0,0,31,13,79,0,55,41 %N A066858 Smallest k>1 such that for each integer x, x^k=x or x^k=0 (mod n); or 0 if no such k exists. %C A066858 By Fermat's little theorem if k exists then k <= n (with equality only if n prime). All terms that are 0 are not squarefree and not prime powers. - Larry Reeves %K A066858 nonn %O A066858 2,1 %A A066858 _Roger Cuculière_, Jan 22 2002 %E A066858 More terms from Larry Reeves (larryr(AT)acm.org), Jun 11 2002