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 A280423 #4 Jan 02 2017 19:16:27
%S A280423 1,1,3,4,7,10,17,23,36,49,71,96,136,180,248,326,437,569,752,967,1261,
%T A280423 1609,2069,2620,3335,4189,5285,6595,8249,10230,12706,15661,19327,
%U A280423 23696,29063,35457,43256,52519,63756,77073,93126,112120,134901,161781,193884,231679
%N A280423 G.f.: Product_{k>=1} (1 + x^(k*(k+1))) / (1 - x^k).
%F A280423 a(n) ~ exp(sqrt(2*n/3)*Pi + 3^(1/4) * (sqrt(2)-1) * Zeta(3/2) * n^(1/4) / 2^(5/4) + 3*(2*sqrt(2)-3) * Zeta(3/2)^2 / (64*Pi)) / (8*sqrt(3)*n).
%t A280423 nmax=60; CoefficientList[Series[Product[(1+x^(k*(k+1)))/(1-x^k), {k, 1, nmax}], {x, 0, nmax}], x]
%Y A280423 Cf. A024940, A000041, A280421.
%K A280423 nonn
%O A280423 0,3
%A A280423 _Vaclav Kotesovec_, Jan 02 2017