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 A353883 #10 May 09 2022 15:19:30
%S A353883 1,0,0,0,6,30,105,315,3388,47628,497115,4172025,37829946,491971194,
%T A353883 7699457857,114432747975,1602464966040,23767387469688,408590795439351,
%U A353883 7756561553900085,149537297087139910,2889288053301888630,58297667473293537597
%N A353883 Expansion of e.g.f. 1/(1 - (x * (exp(x) - 1))^2 / 4).
%F A353883 a(n) = n! * Sum_{k=0..floor(n/4)} (2*k)! * Stirling2(n-2*k,2*k)/(4^k * (n-2*k)!).
%o A353883 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(1-(x*(exp(x)-1))^2/4)))
%o A353883 (PARI) a(n) = n!*sum(k=0, n\4, (2*k)!*stirling(n-2*k, 2*k, 2)/(4^k*(n-2*k)!));
%Y A353883 Cf. A052848, A353884, A353885.
%Y A353883 Cf. A330047, A353880.
%K A353883 nonn
%O A353883 0,5
%A A353883 _Seiichi Manyama_, May 09 2022