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 A306704 #5 Mar 05 2019 18:18:19
%S A306704 1,1,-1,2,-2,0,1,3,-5,-6,11,11,-12,-35,33,35,-22,-102,170,47,-224,
%T A306704 -491,874,695,-598,-2606,2246,1503,-664,-6420,11590,2526,-13762,
%U A306704 -34647,61785,37119,-32372,-181052,147105,104896,12824,-436333,799007,-109587,-868230,-2316921,4447531
%N A306704 Expansion of Sum_{k>=0} x^(k*(k+1)/2) / Product_{j=1..k} (1 + j*x^j).
%t A306704 nmax = 46; CoefficientList[Series[Sum[x^(k (k + 1)/2)/Product[(1 + j x^j), {j, 1, k}], {k, 0, nmax}], {x, 0, nmax}], x]
%Y A306704 Cf. A003406, A204856.
%K A306704 sign
%O A306704 0,4
%A A306704 _Ilya Gutkovskiy_, Mar 05 2019