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 A365989 #9 Sep 25 2023 07:47:05
%S A365989 1,0,0,0,6,0,0,0,1260,40320,0,0,1247400,172972800,6227020800,0,
%T A365989 3405402000,1235025792000,153848927232000,6402373705728000,
%U A365989 19799007228000,14783258730240000,4243499220280320000,545332851008225280000,25852227123135781368000
%N A365989 Expansion of e.g.f. exp( Sum_{k>=0} x^(5*k+4) / (5*k+4) ).
%F A365989 a(0) = 1; a(n) = (n-1)! * Sum_{k=0..floor((n-4)/5)} a(n-5*k-4)/(n-5*k-4)!.
%o A365989 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=0, N\5, x^(5*k+4)/(5*k+4)))))
%Y A365989 Cf. A365969, A365972, A365974.
%Y A365989 Cf. A365895, A365990.
%K A365989 nonn
%O A365989 0,5
%A A365989 _Seiichi Manyama_, Sep 25 2023