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 A377892 #8 Nov 11 2024 06:50:31
%S A377892 1,2,19,352,9885,374486,17907991,1035748260,70334590969,5487022612810,
%T A377892 483655093883451,47541690024105608,5156503816883562325,
%U A377892 611769291578643110238,78812382009451814165695,10956572374811382997014796,1634950184384280878142249969,260653481562714033459279871250
%N A377892 E.g.f. A(x) satisfies A(x) = (1 + x*A(x)^2) * exp(x * A(x)^2).
%F A377892 a(n) = n! * Sum_{k=0..n} (2*n+1)^(k-1) * binomial(2*n+1,n-k)/k!.
%o A377892 (PARI) a(n) = n!*sum(k=0, n, (2*n+1)^(k-1)*binomial(2*n+1, n-k)/k!);
%Y A377892 Cf. A088690, A377893.
%K A377892 nonn
%O A377892 0,2
%A A377892 _Seiichi Manyama_, Nov 11 2024