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 A377830 #10 Nov 09 2024 08:10:54
%S A377830 1,4,45,886,25397,963216,45615553,2595412240,172624541769,
%T A377830 13150155923200,1129371806449301,107987110491257856,
%U A377830 11379014255782146685,1310277285293012678656,163703077517048727256425,22057132253723442887059456,3188342874266180285119069457,492178313447920665621400780800
%N A377830 Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-x)/(1 + x)^3 ).
%H A377830 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A377830 E.g.f. A(x) satisfies A(x) = (1 + x*A(x))^3 * exp(x * A(x)).
%F A377830 a(n) = n! * Sum_{k=0..n} (n+1)^(k-1) * binomial(3*n+3,n-k)/k!.
%o A377830 (PARI) a(n) = n!*sum(k=0, n, (n+1)^(k-1)*binomial(3*n+3, n-k)/k!);
%Y A377830 Cf. A088690, A377829.
%K A377830 nonn
%O A377830 0,2
%A A377830 _Seiichi Manyama_, Nov 09 2024