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 A380675 #9 Jan 30 2025 11:23:35
%S A380675 1,3,27,436,10377,329016,13079971,626414496,35132554449,2259697340800,
%T A380675 164013549475371,13263204195136512,1182645846100592473,
%U A380675 115285805003164594176,12197859187688440506675,1392237638583170475298816,170517388925776876433310369,22307473046095249063001554944
%N A380675 Expansion of e.g.f. (1/x) * Series_Reversion( x * (1 - x)^2 * exp(-x * (1 - x)) ).
%H A380675 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A380675 E.g.f. A(x) satisfies A(x) = exp(x * A(x) * (1 - x*A(x)))/(1 - x*A(x))^2.
%F A380675 a(n) = n! * Sum_{k=0..n} (n+1)^(k-1) * binomial(3*n-2*k+1,n-k)/k!.
%o A380675 (PARI) a(n) = n!*sum(k=0, n, (n+1)^(k-1)*binomial(3*n-2*k+1, n-k)/k!);
%Y A380675 Cf. A377832, A380665, A380666, A380674.
%K A380675 nonn
%O A380675 0,2
%A A380675 _Seiichi Manyama_, Jan 30 2025