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 A380719 #9 Jan 31 2025 09:25:04
%S A380719 1,2,13,157,2817,67541,2033293,73793399,3137724033,153046171657,
%T A380719 8425546124661,516854537135795,34963627698674689,2585888583437930525,
%U A380719 207593192181190597629,17978635157682679541311,1670861912137958623651329,165868047783912942721097873,17517226956387964424430057829
%N A380719 E.g.f. A(x) satisfies A(x) = exp(x / (1 - x*A(x))^2) / (1 - x*A(x)).
%F A380719 a(n) = n! * Sum_{k=0..n} (n-k+1)^(k-1) * binomial(2*n,n-k)/k!.
%o A380719 (PARI) a(n) = n!*sum(k=0, n, (n-k+1)^(k-1)*binomial(2*n, n-k)/k!);
%Y A380719 Cf. A380663, A380718.
%K A380719 nonn
%O A380719 0,2
%A A380719 _Seiichi Manyama_, Jan 30 2025