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 A376438 #12 Sep 23 2024 09:28:20
%S A376438 1,0,0,12,24,40,10860,85764,446992,57788784,1008736020,10835748220,
%T A376438 965748698904,28637803537512,519426455756572,37968161216666100,
%U A376438 1626852405783259680,44177643556314690784,2957776991432290423332,163869985958022692795628,6132727345895339422510120,405409522521171206216078040
%N A376438 Expansion of e.g.f. (1/x) * Series_Reversion( x*(1 - x^2*(exp(x) - 1))^2 ).
%H A376438 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A376438 E.g.f. A(x) satisfies A(x) = 1/(1 - x^2*A(x)^2 * (exp(x*A(x)) - 1))^2.
%F A376438 a(n) = (2 * n!/(2*n+2)!) * Sum_{k=0..floor(n/3)} (2*n+k+1)! * Stirling2(n-2*k,k)/(n-2*k)!.
%o A376438 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(serreverse(x*(1-x^2*(exp(x)-1))^2)/x))
%o A376438 (PARI) a(n) = 2*n!*sum(k=0, n\3, (2*n+k+1)!*stirling(n-2*k, k, 2)/(n-2*k)!)/(2*n+2)!;
%Y A376438 Cf. A376381, A376389.
%Y A376438 Cf. A375662.
%K A376438 nonn
%O A376438 0,4
%A A376438 _Seiichi Manyama_, Sep 22 2024