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 A117736 #3 Mar 30 2012 17:34:20
%S A117736 0,0,1,5,20,116,696,5016,40128,361152,3611520,39899520,478794240,
%T A117736 6226813440,87175388160,1307630822400,20922093158400,355686731366400,
%U A117736 6402361164595200,121645087867699200,2432901757353984000
%N A117736 factorial(n) - A049614(n).
%F A117736 a(n) =n!- A049614(n) = A000142(n)-A049614(n).
%t A117736 f[n_] := If[PrimeQ[n] == True, 1, n] cf[0] = 1; cf[n_Integer?Positive] := cf[n] = f[n]*cf[n - 1] g[n_] := If[PrimeQ[n] == True, n, 1] p[0] = 1; p[n_Integer?Positive] := p[n] = g[n]*p[n - 1] Table[n! - cf[n], {n, 0, 20}]
%Y A117736 Cf. A034386, A117683.
%K A117736 nonn
%O A117736 0,4
%A A117736 _Roger L. Bagula_, Apr 14 2006
%E A117736 Edited by the Assoc. Eds. of the OEIS, Jun 27 2010