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 A371018 #10 Mar 08 2024 08:00:08
%S A371018 1,0,2,6,60,620,7950,129402,2365496,50512968,1208642490,32223422990,
%T A371018 947694971652,30435132773916,1061061668979494,39889366397571810,
%U A371018 1608910488000292080,69305890226183224592,3175519952912430375666,154216789672147809137046
%N A371018 Expansion of e.g.f. (1/x) * Series_Reversion( x/(1 + x^2*exp(x)) ).
%H A371018 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A371018 a(n) = (n!/(n+1)) * Sum_{k=0..floor(n/2)} k^(n-2*k) * binomial(n+1,k)/(n-2*k)!.
%o A371018 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(serreverse(x/(1+x^2*exp(x)))/x))
%o A371018 (PARI) a(n) = n!*sum(k=0, n\2, k^(n-2*k)*binomial(n+1, k)/(n-2*k)!)/(n+1);
%Y A371018 Cf. A161633, A371019.
%Y A371018 Cf. A365283.
%K A371018 nonn
%O A371018 0,3
%A A371018 _Seiichi Manyama_, Mar 08 2024