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 A379861 #10 Jan 05 2025 09:58:41
%S A379861 1,1,5,38,441,6714,128245,2943562,79049201,2432351618,84408126621,
%T A379861 3261942050058,138946757581225,6468600047278498,326782092756236741,
%U A379861 17805164917279808234,1040857709162817298401,64983981546315031200258,4315627103007355018430509
%N A379861 Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(x)/(1 + x*exp(x))^2 ).
%H A379861 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A379861 E.g.f. A(x) satisfies A(x) = exp(-x*A) * (1 + x * A(x) * exp(x*A(x)))^2.
%F A379861 a(n) = (n!/(n+1)) * Sum_{k=0..n} (-n+k-1)^(n-k) * binomial(2*n+2,k)/(n-k)!.
%o A379861 (PARI) a(n) = n!*sum(k=0, n, (-n+k-1)^(n-k)*binomial(2*n+2, k)/(n-k)!)/(n+1);
%Y A379861 Cf. A377553, A379862.
%K A379861 nonn
%O A379861 0,3
%A A379861 _Seiichi Manyama_, Jan 04 2025