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 A387092 #13 Aug 20 2025 06:49:21
%S A387092 1,5,73,1273,23993,472483,9570669,197720403,4144499289,87850211830,
%T A387092 1878702271039,40466493877812,876838997392189,19095109351916182,
%U A387092 417622272948538767,9167498552774475792,201891862924784199321,4458815817948146064915
%N A387092 Expansion of B(x)/sqrt(1 + 8*(B(x)-1)/9), where B(x) is the g.f. of A169958.
%F A387092 Sum_{k=0..n} a(k) * a(n-k) = A387091(n).
%F A387092 G.f.: 1/sqrt(1 - x*g^7*(9+g)) where g = 1+x*g^9 is the g.f. of A062994.
%F A387092 G.f.: g/sqrt(9-8*g) where g = 1+x*g^9 is the g.f. of A062994.
%F A387092 a(n) ~ 3^(18*n + 3/2) / (Gamma(1/4) * n^(3/4) * 2^(24*n + 5/2)). - _Vaclav Kotesovec_, Aug 20 2025
%t A387092 nmax = 25; CoefficientList[Series[Sum[Binomial[9*n, n]*x^n, {n, 0, nmax}] / Sqrt[1 + 8*(Sum[Binomial[9*n, n]*x^n, {n, 0, nmax}] - 1)/9], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Aug 20 2025 *)
%Y A387092 Cf. A226706, A383965.
%Y A387092 Cf. A062994, A169958, A387091.
%K A387092 nonn
%O A387092 0,2
%A A387092 _Seiichi Manyama_, Aug 16 2025