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 A376439 #11 Sep 23 2024 09:28:27
%S A376439 1,0,0,18,36,60,23850,189126,988008,184207176,3254640750,35132272890,
%T A376439 4418970811596,134653558474188,2463781708180338,246532610826062190,
%U A376439 11098269938629561680,305828547775319369616,27016544700449293891158
%N A376439 Expansion of e.g.f. (1/x) * Series_Reversion( x*(1 - x^2*(exp(x) - 1))^3 ).
%H A376439 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A376439 E.g.f. A(x) satisfies A(x) = 1/(1 - x^2*A(x)^2 * (exp(x*A(x)) - 1))^3.
%F A376439 a(n) = (3 * n!/(3*n+3)!) * Sum_{k=0..floor(n/3)} (3*n+k+2)! * Stirling2(n-2*k,k)/(n-2*k)!.
%o A376439 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(serreverse(x*(1-x^2*(exp(x)-1))^3)/x))
%o A376439 (PARI) a(n) = 3*n!*sum(k=0, n\3, (3*n+k+2)!*stirling(n-2*k, k, 2)/(n-2*k)!)/(3*n+3)!;
%Y A376439 Cf. A376382, A376390.
%Y A376439 Cf. A375663.
%K A376439 nonn
%O A376439 0,4
%A A376439 _Seiichi Manyama_, Sep 22 2024