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 A370792 #7 Mar 02 2024 08:00:41
%S A370792 1,10,39,390,1521,7830,49518,207360,951102,4264650,22185657,89579520,
%T A370792 401428224,1676401110,7172977275,31972081050,130330236546,
%U A370792 537393139200,2213787635712,8988968449530,36073295687070,150459195064320,590262148332288,2362876271009370,9314694641056095
%N A370792 Expansion of Product_{k>=1} (1 + 3^(k+1)*x^k) * (1 + 3^(k-1)*x^k).
%C A370792 In general, if d >= 1 and g.f. = Product_{k>=1} (1 + d^(k+1)*x^k) * (1 + d^(k-1)*x^k), then a(n) ~ d^(n + 1/2) * exp(sqrt(2*n*(Pi^2/3 + log(d)^2))) * (Pi^2/3 + log(d)^2)^(1/4) / (2^(5/4) * sqrt(Pi) * (d+1) * n^(3/4)).
%F A370792 a(n) ~ 3^(n + 1/2) * exp(sqrt(2*n*(Pi^2/3 + log(3)^2))) * (Pi^2/3 + log(3)^2)^(1/4) / (2^(13/4) * sqrt(Pi) * n^(3/4)).
%t A370792 nmax = 25; CoefficientList[Series[Product[(1+3^(k+1)*x^k)*(1+3^(k-1)*x^k), {k, 1, nmax}], {x, 0, nmax}], x]
%Y A370792 Cf. A032308, A344062.
%Y A370792 Cf. A022567 (d=1), A370761 (d=2).
%K A370792 nonn
%O A370792 0,2
%A A370792 _Vaclav Kotesovec_, Mar 02 2024