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 A353226 #21 May 04 2022 05:09:35
%S A353226 1,0,0,6,0,60,360,1680,20160,151200,1663200,17962560,219542400,
%T A353226 2854051200,40441040640,606356150400,9793028044800,166481476761600,
%U A353226 3017626733721600,57359043873331200,1153275200453376000,24233844054131712000,535361100608439705600
%N A353226 Expansion of e.g.f. (1 - x^2)^(-x).
%F A353226 a(0) = 1; a(n) = (n-1)! * Sum_{k=2..floor((n+1)/2)} (2*k-1)/(k-1) * a(n-2*k+1)/(n-2*k+1)!.
%F A353226 a(n) = n! * Sum_{k=0..floor(n/2)} |Stirling1(k,n-2*k)|/k!.
%F A353226 a(n) ~ sqrt(2*Pi) * n^(n + 1/2) / (2*exp(n)). - _Vaclav Kotesovec_, May 04 2022
%o A353226 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace((1-x^2)^(-x)))
%o A353226 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(-x*log(1-x^2))))
%o A353226 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=(i-1)!*sum(j=2, (i+1)\2, (2*j-1)/(j-1)*v[i-2*j+2]/(i-2*j+1)!)); v;
%o A353226 (PARI) a(n) = n!*sum(k=0, n\2, abs(stirling(k, n-2*k, 1))/k!);
%Y A353226 Cf. A066166, A121452, A351155, A353227.
%K A353226 nonn
%O A353226 0,4
%A A353226 _Seiichi Manyama_, May 01 2022