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 A231549 #13 Nov 18 2013 15:29:59
%S A231549 1,1,1,4,2,8,3,3,3,4,1,2,3,5,8,4,10,2,11,9,5,5,7,3,14,18,1,40,24,5,5,
%T A231549 18,8,20,2,49,1,3,5,28,1,17,38,27,11,16,10,3,24,270,2,45,2,15,175,64,
%U A231549 17,6,4,3,8,18,13,17,65,32,12,7,72,13,21,33,1,24,36,76,1
%N A231549 Least k>0 such that k!*n!+1 is a prime, or 0 if no such k exists.
%C A231549 Indices of 1's: A002981.
%t A231549 Table[k = 1; While[! PrimeQ[k!*n! + 1], k++]; k, {n, 100}] (* _T. D. Noe_, Nov 18 2013 *)
%Y A231549 Cf. A002981, A035093, A057217, A075757, A075758, A231901.
%K A231549 nonn
%O A231549 1,4
%A A231549 _Alex Ratushnyak_, Nov 15 2013