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 A381450 #12 Feb 24 2025 08:52:23
%S A381450 1,3,24,339,7056,195855,6819840,286105071,14055420288,791783681499,
%T A381450 50327779368960,3563709848656683,278223968271034368,
%U A381450 23744747385054558759,2199369837961901789184,219748696455778150645575,23559108001707680103628800,2697737574531326391439989171
%N A381450 Expansion of e.g.f. (1/x) * Series_Reversion( x/(1 + x * cosh(x))^3 ).
%C A381450 As stated in the comment of A185951, A185951(n,0) = 0^n.
%H A381450 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A381450 E.g.f. A(x) satisfies A(x) = (1 + x*A(x) * cosh(x*A(x)))^3.
%F A381450 E.g.f.: B(x)^3, where B(x) is the e.g.f. of A381448.
%F A381450 a(n) = (1/(n+1)) * Sum_{k=0..n} k! * binomial(3*n+3,k) * A185951(n,k).
%o A381450 (PARI) a185951(n, k) = binomial(n, k)/2^k*sum(j=0, k, (2*j-k)^(n-k)*binomial(k, j));
%o A381450 a(n) = sum(k=0, n, k!*binomial(3*n+3, k)*a185951(n, k))/(n+1);
%Y A381450 Cf. A381171, A381449.
%Y A381450 Cf. A377554, A381443.
%Y A381450 Cf. A185951, A381448.
%K A381450 nonn
%O A381450 0,2
%A A381450 _Seiichi Manyama_, Feb 23 2025