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 A279360 #16 Feb 04 2021 14:42:10 %S A279360 1,2,0,0,2,4,0,0,0,2,4,0,0,4,8,0,2,4,0,0,4,8,0,0,0,6,12,0,0,12,24,0,0, %T A279360 0,4,8,2,4,8,16,4,12,8,0,0,12,24,0,0,10,28,16,4,12,24,32,8,16,4,8,0, %U A279360 12,32,16,2,32,56,0,4,16,24,16,0,4,36,56,0,16 %N A279360 Expansion of Product_{k>=1} (1+2*x^(k^2)). %H A279360 Vaclav Kotesovec, <a href="/A279360/b279360.txt">Table of n, a(n) for n = 0..10000</a> %F A279360 a(n) ~ c^(1/3) * exp(3 * 2^(-4/3) * c^(2/3) * Pi^(1/3) * n^(1/3)) / (3 * 2^(2/3) * Pi^(1/3) * n^(5/6)), where c = -PolyLog(3/2, -2) = 1.28138038315976963883198... . - _Vaclav Kotesovec_, Dec 12 2016 %F A279360 From _Alois P. Heinz_, Feb 03 2021: (Start) %F A279360 a(n) = Sum_{k>=0} 2^k * A341040(n,k). %F A279360 a(n) = 0 <=> n in { A001422 }. (End) %t A279360 nmax = 200; CoefficientList[Series[Product[(1+2*x^(k^2)), {k, 1, nmax}], {x, 0, nmax}], x] %t A279360 nmax = 200; nn = Floor[Sqrt[nmax]]+1; poly = ConstantArray[0, nn^2 + 1]; poly[[1]] = 1; poly[[2]] = 2; poly[[3]] = 0; Do[Do[poly[[j + 1]] += 2*poly[[j - k^2 + 1]], {j, nn^2, k^2, -1}];, {k, 2, nn}]; Take[poly, nmax+1] %Y A279360 Cf. A001422, A032302, A033461, A279226, A279368, A341040. %K A279360 nonn %O A279360 0,2 %A A279360 _Vaclav Kotesovec_, Dec 10 2016