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 A375680 #11 Sep 01 2024 10:13:25
%S A375680 1,0,0,12,0,120,2160,3360,120960,1632960,9979200,255467520,3592512000,
%T A375680 45664819200,1070840010240,18027225216000,340344048844800,
%U A375680 8174882722406400,169308486085939200,4019018956285132800,104511967278630912000,2606273308503760896000
%N A375680 Expansion of e.g.f. 1 / (1 + x * log(1 - x^2))^2.
%F A375680 E.g.f.: B(x)^2, where B(x) is the e.g.f. of A375561.
%F A375680 a(n) = n! * Sum_{k=0..floor(n/2)} (n-2*k+1)! * |Stirling1(k,n-2*k)|/k!.
%o A375680 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(1+x*log(1-x^2))^2))
%o A375680 (PARI) a(n) = n!*sum(k=0, n\2, (n-2*k+1)!*abs(stirling(k, n-2*k, 1))/k!);
%Y A375680 Cf. A375561, A375681.
%Y A375680 Cf. A375664.
%K A375680 nonn
%O A375680 0,4
%A A375680 _Seiichi Manyama_, Aug 23 2024