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 A364978 #8 Aug 15 2023 07:42:01
%S A364978 1,1,2,15,124,1565,23886,446887,9787352,246408633,7010910010,
%T A364978 222438284651,7788393551412,298293192119221,12406118302851014,
%U A364978 556817903190669135,26825727269937929776,1380790608848655193457,75625529930102546486514
%N A364978 E.g.f. satisfies A(x) = 1 + x*exp(x*A(x)^2).
%F A364978 a(n) = n! * Sum_{k=0..n} k^(n-k) * binomial(2*n-2*k+1,k)/( (2*n-2*k+1)*(n-k)! ).
%o A364978 (PARI) a(n) = n!*sum(k=0, n, k^(n-k)*binomial(2*n-2*k+1, k)/((2*n-2*k+1)*(n-k)!));
%Y A364978 Cf. A161631, A364979.
%K A364978 nonn
%O A364978 0,3
%A A364978 _Seiichi Manyama_, Aug 15 2023