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 A380880 #11 Feb 07 2025 05:36:34
%S A380880 1,3,33,657,19317,756663,37153071,2196991317,152107121481,
%T A380880 12074764795947,1081507189545219,107911010079715857,
%U A380880 11871250914793342797,1427601609871824349407,186326851375925627135127,26232637698244127999077677,3962908338833364902518738449,639433805204122165558890771027
%N A380880 Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-3*x*exp(x)) ).
%H A380880 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A380880 E.g.f. A(x) satisfies A(x) = exp(3 * x * A(x) * exp(x * A(x))).
%F A380880 E.g.f.: B(x)^3, where B(x) is the e.g.f. of A380881.
%F A380880 a(n) = 3 * Sum_{k=0..n} k^(n-k) * (3*n+3)^(k-1) * binomial(n,k).
%o A380880 (PARI) a(n) = 3*sum(k=0, n, k^(n-k)*(3*n+3)^(k-1)*binomial(n, k));
%Y A380880 Cf. A162695, A380879.
%Y A380880 Cf. A380881.
%K A380880 nonn
%O A380880 0,2
%A A380880 _Seiichi Manyama_, Feb 07 2025