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 A377554 #9 Nov 01 2024 09:30:28
%S A377554 1,3,30,537,14124,493695,21601458,1137294039,70064934600,
%T A377554 4947238170747,394022075650590,34951812094581723,3417754921150904172,
%U A377554 365287875167708973831,42368411854713294141834,5300422308901745571018735,711465905597330333014408848,101995745742232833085109746803
%N A377554 Expansion of e.g.f. (1/x) * Series_Reversion( x/(1 + x*exp(x))^3 ).
%H A377554 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A377554 E.g.f. satisfies A(x) = (1 + x * A(x) * exp(x*A(x)))^3.
%F A377554 E.g.f.: B(x)^3, where B(x) is the e.g.f. of A364986.
%F A377554 a(n) = (n!/(n+1)) * Sum_{k=0..n} k^(n-k) * binomial(3*n+3,k)/(n-k)!.
%o A377554 (PARI) a(n) = n!*sum(k=0, n, k^(n-k)*binomial(3*n+3, k)/(n-k)!)/(n+1);
%Y A377554 Cf. A161633, A377553.
%Y A377554 Cf. A364986.
%K A377554 nonn
%O A377554 0,2
%A A377554 _Seiichi Manyama_, Nov 01 2024