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 A363113 #9 May 15 2023 08:46:51
%S A363113 1,2,30,621,14196,351802,9179386,248533626,6917835992,196730606200,
%T A363113 5691264122213,166961281712818,4955321842136163,148522859439511133,
%U A363113 4489164688548477495,136677755757518772050,4187859771944659634378,129039023692329781903247,3995878021838502688832856
%N A363113 Expansion of g.f. A(x) satisfying 1 = Sum_{n=-oo..+oo} x^n * (2*A(x) - x^n)^(3*n-1).
%H A363113 Paul D. Hanna, <a href="/A363113/b363113.txt">Table of n, a(n) for n = 0..300</a>
%F A363113 Generating function A(x) = Sum_{n>=0} a(n)*x^n satisfies the following formulas.
%F A363113 (1) 1 = Sum_{n=-oo..+oo} x^n * (2*A(x) - x^n)^(3*n-1).
%F A363113 (2) 1 = Sum_{n=-oo..+oo} (-1)^(n+1) * x^(3*n^2) / (1 - 2*A(x)*x^n)^(3*n+1).
%e A363113 G.f.: A(x) = 1 + 2*x + 30*x^2 + 621*x^3 + 14196*x^4 + 351802*x^5 + 9179386*x^6 + 248533626*x^7 + 6917835992*x^8 + 196730606200*x^9 + ...
%o A363113 (PARI) {a(n) = my(A=[1]); for(i=1, n, A=concat(A, 0);
%o A363113 A[#A] = polcoeff(-1 + sum(m=-#A, #A, x^m * (2*Ser(A) - x^m)^(3*m-1) ), #A-1)/2); A[n+1]}
%o A363113 for(n=0, 30, print1(a(n), ", "))
%o A363113 (PARI) {a(n) = my(A=[1]); for(i=1, n, A=concat(A, 0);
%o A363113 A[#A] = polcoeff(-1 + sum(m=-#A, #A, (-1)^(m+1) * x^(3*m^2)/(1 - 2*Ser(A)*x^m)^(3*m+1) ), #A-1)/2); A[n+1]}
%o A363113 for(n=0, 30, print1(a(n), ", "))
%Y A363113 Cf. A357227, A363112, A363114.
%Y A363113 Cf. A361773.
%K A363113 nonn
%O A363113 0,2
%A A363113 _Paul D. Hanna_, May 14 2023