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 A191549 #4 Mar 30 2012 18:35:55 %S A191549 10,1,644,1,3663738,2,2,1,2,1,910,417,2,1,8,1, %T A191549 39547926178950768553863180373284,33,6,1,2,1943509,4,3,88,1,248,1, %U A191549 42284686073214306750946346164468593496471283975461929077356416,3,22896,1481424868782,1634,1,22260,1077,2,1 %N A191549 Least number k such that kn + 1 is a prime dividing prime(n)^n - 1. %e A191549 a(3) = 10 because 10*3 + 1 = 31 and this number is the smallest prime divisor of the form kn+1 %e A191549 dividing prime(3)^3 - 1 = 5^3-1 = 124 = 2^2*31. %t A191549 Table[p=First/@FactorInteger[Prime[ n]^n-1]; (Select[p, Mod[#1, n] == 1 &, %t A191549 1][[1]] - 1)/(n), {n, 3, 40}] %Y A191549 Cf. A191548. %K A191549 nonn %O A191549 3,1 %A A191549 _Michel Lagneau_, Jun 05 2011