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 A261389 #13 Jan 30 2017 02:52:30
%S A261389 1,6,30,128,486,1704,5604,17484,52206,150118,417696,1128984,2973476,
%T A261389 7650720,19272432,47616568,115570014,275921460,648771802,1503889488,
%U A261389 3439990344,7770915816,17349229908,38306180052,83694778556,181052778078,387976101432,823939048560
%N A261389 Expansion of Product_{k>=1} ((1+x^k)/(1-x^k))^(3*k).
%C A261389 Convolution of A255610 and A027346.
%C A261389 In general, if g.f. = Product_{k>=1} ((1+x^k)/(1-x^k))^(t*k) and t>=1, then a(n) ~ exp(t/12 + 3/2 * (7*t*Zeta(3)/2)^(1/3) * n^(2/3)) * t^(1/6 + t/36) * (7*Zeta(3))^(1/6 + t/36) / (A^t * 2^(2/3 + t/9) * sqrt(3*Pi) * n^(2/3 + t/36)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant.
%H A261389 G. C. Greubel, <a href="/A261389/b261389.txt">Table of n, a(n) for n = 0..1000</a>
%H A261389 Vaclav Kotesovec, <a href="http://arxiv.org/abs/1509.08708">A method of finding the asymptotics of q-series based on the convolution of generating functions</a>, arXiv:1509.08708 [math.CO], Sep 30 2015, p. 19.
%F A261389 a(n) ~ exp(1/4 + 3/2 * (21*Zeta(3)/2)^(1/3) * n^(2/3)) * (7*Zeta(3)/3)^(1/4) / (2 * A^3 * sqrt(Pi) * n^(3/4)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant.
%t A261389 nmax = 40; CoefficientList[Series[Product[((1+x^k)/(1-x^k))^(3*k), {k, 1, nmax}], {x, 0, nmax}], x]
%Y A261389 Cf. A156616 (t=1), A261386 (t=2).
%Y A261389 Cf. A015128, A027346, A027906, A193427, A255610.
%K A261389 nonn
%O A261389 0,2
%A A261389 _Vaclav Kotesovec_, Aug 17 2015