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 A381376 #10 Feb 22 2025 09:56:27
%S A381376 1,1,2,9,96,1385,22080,403417,8829184,227956689,6667822080,
%T A381376 215780258441,7674505073664,298885308910201,12661212551163904,
%U A381376 578940699178779225,28400662193828659200,1488075298726340008097,82965096417136263561216,4904558063539270185865609
%N A381376 E.g.f. A(x) satisfies A(x) = 1/( 1 - x * cosh(x * A(x)^2) ).
%C A381376 As stated in the comment of A185951, A185951(n,0) = 0^n.
%F A381376 a(n) = Sum_{k=0..n} k! * binomial(2*n-k+1,k)/(2*n-k+1) * A185951(n,k).
%o A381376 (PARI) a185951(n, k) = binomial(n, k)/2^k*sum(j=0, k, (2*j-k)^(n-k)*binomial(k, j));
%o A381376 a(n) = sum(k=0, n, k!*binomial(2*n-k+1, k)/(2*n-k+1)*a185951(n, k));
%Y A381376 Cf. A381171, A381300.
%Y A381376 Cf. A185951, A381377.
%K A381376 nonn
%O A381376 0,3
%A A381376 _Seiichi Manyama_, Feb 22 2025