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 A370878 #9 Mar 04 2024 11:53:34
%S A370878 1,1,2,7,40,320,3190,37870,526400,8434720,153092800,3099958400,
%T A370878 69237737800,1691184094600,44855672061200,1283910696468400,
%U A370878 39445370739174400,1294688750568012800,45213628130719048000,1673957726914620347200,65493419262155812928000
%N A370878 Expansion of e.g.f. (1/x) * Series_Reversion( x/(x + exp(x^3/6)) ).
%H A370878 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A370878 a(n) = n! * Sum_{k=0..floor(n/3)} (3*k+1)^(k-1) * binomial(n,3*k)/(6^k * k!).
%o A370878 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(serreverse(x/(x+exp(x^3/6)))/x))
%o A370878 (PARI) a(n) = n!*sum(k=0, n\3, (3*k+1)^(k-1)*binomial(n, 3*k)/(6^k*k!));
%Y A370878 Cf. A352410, A370877.
%K A370878 nonn
%O A370878 0,3
%A A370878 _Seiichi Manyama_, Mar 03 2024