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 A361773 #11 Apr 22 2025 21:55:52
%S A361773 1,2,34,677,15660,393790,10433402,286990626,8117763488,234635708480,
%T A361773 6899771599141,205768408153474,6208628685564955,189188990142419693,
%U A361773 5813805339043713267,179968235623379467274,5606627898452185950618,175650401043239524832783,5530500462355496324862920
%N A361773 Expansion of g.f. A(x) satisfying 1 = Sum_{n=-oo..+oo} x^n * (2*A(x) - (-x)^n)^(3*n-1).
%H A361773 Paul D. Hanna, <a href="/A361773/b361773.txt">Table of n, a(n) for n = 0..300</a>
%F A361773 G.f. A(x) = Sum_{n>=0} a(n)*x^n may be defined by the following.
%F A361773 (1) 1 = Sum_{n=-oo..+oo} x^n * (2*A(x) - (-x)^n)^(3*n-1).
%F A361773 (2) 1 = Sum_{n=-oo..+oo} (-1)^(n+1) * x^(3*n^2) / (1 - 2*A(x)*(-x)^n)^(3*n+1).
%e A361773 G.f.: A(x) = 1 + 2*x + 34*x^2 + 677*x^3 + 15660*x^4 + 393790*x^5 + 10433402*x^6 + 286990626*x^7 + 8117763488*x^8 + 234635708480*x^9 + 6899771599141*x^10 + ...
%o A361773 (PARI) {a(n) = my(A=[1]); for(i=1, n, A=concat(A, 0);
%o A361773 A[#A] = polcoeff( sum(m=-#A, #A, x^m * (2*Ser(A) - (-x)^m)^(3*m-1) ), #A-1)/2); A[n+1]}
%o A361773 for(n=0, 30, print1(a(n), ", "))
%Y A361773 Cf. A361771, A361772, A361774.
%Y A361773 Cf. A363113, A355865, A357227, A359712, A357232.
%K A361773 nonn
%O A361773 0,2
%A A361773 _Paul D. Hanna_, May 13 2023