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 A380779 #13 Feb 03 2025 11:09:01
%S A380779 1,3,23,298,5529,134496,4062631,146903184,6193969137,298577002240,
%T A380779 16204658051031,978156957629952,65017249611283657,4719532271850590208,
%U A380779 371519503997940966375,31526820740816885549056,2869134152226896957509089,278763390556764407051452416
%N A380779 Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-x / (1 + x)) / (1 + x)^2 ).
%H A380779 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A380779 E.g.f. A(x) satisfies A(x) = exp( x * A(x) / (1 + x*A(x)) ) * (1 + x*A(x))^2.
%F A380779 a(n) = n! * Sum_{k=0..n} (n+1)^(k-1) * binomial(2*n-k+2,n-k)/k!.
%o A380779 (PARI) a(n, q=1, r=1, s=1, t=-1, u=2) = q*n!*sum(k=0, n, (r*n+(s-r)*k+q)^(k-1)*binomial(r*u*n+((s-r)*u+t)*k+q*u, n-k)/k!);
%Y A380779 Cf. A377829, A380778, A380780, A380781.
%Y A380779 Cf. A380675.
%K A380779 nonn
%O A380779 0,2
%A A380779 _Seiichi Manyama_, Feb 02 2025