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 A377392 #13 Oct 27 2024 09:03:48
%S A377392 1,0,4,6,224,1330,42912,548114,18337440,382829346,14098368080,
%T A377392 413342914402,17124811116624,644015140354898,30163665817167456,
%U A377392 1375047846420311730,72583022771706823232,3866142693873431519554,228486372085027819754928,13871056133441358772777154
%N A377392 Expansion of e.g.f. (1/x) * Series_Reversion( x/(1 + x*(exp(x) - 1))^2 ).
%H A377392 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A377392 E.g.f. satisfies A(x) = ( 1 + x*A(x) * (exp(x*A(x)) - 1) )^2.
%F A377392 E.g.f.: B(x)^2, where B(x) is the e.g.f. of A371270.
%F A377392 a(n) = 2 * n! * (2*n+1)! * Sum_{k=0..floor(n/2)} Stirling2(n-k,k)/( (n-k)! * (2*n-k+2)! ).
%o A377392 (PARI) a(n) = 2*n!*(2*n+1)!*sum(k=0, n\2, stirling(n-k, k, 2)/((n-k)!*(2*n-k+2)!));
%Y A377392 Cf. A371119, A377393.
%Y A377392 Cf. A371270.
%K A377392 nonn
%O A377392 0,3
%A A377392 _Seiichi Manyama_, Oct 27 2024