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 A366564 #13 Dec 15 2023 09:10:11
%S A366564 0,0,0,6,12,20,390,2562,11816,166392,1970730,17131070,241009692,
%T A366564 3861669396,51411143966,828234487290,15865154629200,283329069136112,
%U A366564 5431892804244306,119420738547382134,2628980439169097540,59707303735169923980,1488953374718002643142
%N A366564 Expansion of e.g.f. -log(1 - x^2 * (exp(x) - 1)).
%F A366564 a(n) = n! * Sum_{k=1..floor(n/3)} (k-1)! * Stirling2(n-2*k,k)/(n-2*k)!.
%o A366564 (PARI) a(n) = n!*sum(k=1, n\3, (k-1)!*stirling(n-2*k, k, 2)/(n-2*k)!);
%Y A366564 Cf. A052858, A366751.
%Y A366564 Cf. A366459, A368173.
%K A366564 nonn
%O A366564 0,4
%A A366564 _Seiichi Manyama_, Dec 15 2023