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 A381407 #9 Feb 23 2025 08:01:19
%S A381407 1,1,1,4,61,756,8581,125168,2577849,60269968,1469636041,39496750272,
%T A381407 1212192326005,41147125079360,1496063100479949,58263746530145536,
%U A381407 2447130544401729649,110270888250759852288,5279535712822539622033,267412182631190346232832
%N A381407 E.g.f. A(x) satisfies A(x) = exp( x * cosh(x * A(x)^2) ).
%C A381407 As stated in the comment of A185951, A185951(n,0) = 0^n.
%F A381407 a(n) = Sum_{k=0..n} (2*n-2*k+1)^(k-1) * A185951(n,k).
%o A381407 (PARI) a185951(n, k) = binomial(n, k)/2^k*sum(j=0, k, (2*j-k)^(n-k)*binomial(k, j));
%o A381407 a(n) = sum(k=0, n, (2*n-2*k+1)^(k-1)*a185951(n, k));
%Y A381407 Cf. A185951, A381376.
%K A381407 nonn
%O A381407 0,4
%A A381407 _Seiichi Manyama_, Feb 23 2025