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 A381300 #8 Feb 20 2025 08:39:24
%S A381300 1,1,2,9,60,485,4800,57547,804160,12783969,228447360,4539156941,
%T A381300 99244045824,2367795157741,61230675251200,1706241143585175,
%U A381300 50971847057326080,1625178125581055297,55087299146009640960,1978201530490562626609,75025096312729021972480
%N A381300 E.g.f. A(x) satisfies A(x) = 1/( 1 - x * cosh(x * A(x)^(1/2)) ).
%C A381300 As stated in the comment of A185951, A185951(n,0) = 0^n.
%F A381300 a(n) = Sum_{k=0..n} k! * binomial(n/2+k/2+1,k)/(n/2+k/2+1) * A185951(n,k).
%o A381300 (PARI) a185951(n, k) = binomial(n, k)/2^k*sum(j=0, k, (2*j-k)^(n-k)*binomial(k, j));
%o A381300 a(n) = sum(k=0, n, k!*binomial(n/2+k/2+1, k)/(n/2+k/2+1)*a185951(n, k));
%Y A381300 Cf. A185951.
%K A381300 nonn
%O A381300 0,3
%A A381300 _Seiichi Manyama_, Feb 19 2025