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 A298850 #20 Mar 09 2018 21:15:34
%S A298850 1,1,0,3,3,0,9,9,0,19,29,10,33,63,30,66,156,90,110,300,235,276,561,
%T A298850 465,558,1083,1065,1154,1877,1983,2295,3834,3879,3861,6858,7452,7561,
%U A298850 12613,13252,13057,22161,25569,24582,35985,44193,44970,63495,79105,77143,104046,134820,138759,182511,222600
%N A298850 Expansion of Product_{k>=1} (1 + x^(k*(k+1)/2))^(k*(k+1)/2).
%F A298850 G.f.: Product_{k>=1} (1 + x^A000217(k))^A000217(k).
%t A298850 nmax = 53; CoefficientList[Series[Product[(1 + x^(k (k + 1)/2))^(k (k + 1)/2), {k, 1, nmax}], {x, 0, nmax}], x]
%Y A298850 Cf. A000217, A024940, A027999, A028377, A291649, A298730.
%K A298850 nonn
%O A298850 0,4
%A A298850 _Ilya Gutkovskiy_, Mar 09 2018