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 A356504 #6 Aug 10 2022 07:56:44
%S A356504 1,4,84,2568,94390,3863496,169713208,7836945872,375608185758,
%T A356504 18527792412380,935129979113044,48088668037229040,2511680568602631894,
%U A356504 132918633258508425944,7113508747197660153120,384416086900675623039520,20951080869890118976964642
%N A356504 a(n) = A356500(2*n, 2*n+1) for n >= 0.
%C A356504 Triangle A356500 describes the coefficients in G(x,y) that satisfies: y = Sum_{n=-oo..+oo} (-x)^(n^2) * G(x,y)^((n-1)^2).
%o A356504 (PARI) {A356500(n,k) = my(A=[y],M); for(i=1,n, A = concat(A,0); M = ceil(sqrt(n+1));
%o A356504 A[#A] = -polcoeff( sum(m=-M,M, (-x)^(m^2)*Ser(A)^((m-1)^2)), #A-1)); polcoeff(A[n+1],k,y) }
%o A356504 for(n=0,20, print1( A356500(2*n, 2*n+1),", "))
%Y A356504 Cf. A356500, A356505, A356506.
%K A356504 nonn
%O A356504 0,2
%A A356504 _Paul D. Hanna_, Aug 09 2022