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 A372500 #8 May 04 2024 09:26:23
%S A372500 0,1,12,-45,1404,-33048,684288,-5847309,-440129376,30809872071,
%T A372500 -952939532952,-1846906652457,1545045542366472,-30949156972076031,
%U A372500 -4367665752590389608,253458876292612253442,14695464346775699515704,-2012792131604632851142020
%N A372500 G.f. A(x) satisfies A(A(A(x))) = Sum_{k>=1} k^2 * 9^(k-1) * x^k.
%e A372500 A(A(x)) = x + 24*x^2 + 198*x^3 + 1836*x^4 + 8667*x^5 - 139968*x^6 + 11814903*x^7 - 371755008*x^8 + ...
%Y A372500 Cf. A372493, A372499.
%K A372500 sign
%O A372500 0,3
%A A372500 _Seiichi Manyama_, May 03 2024