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 A284628 #26 Apr 15 2017 19:38:44
%S A284628 1,-1,1,-4,4,-9,15,-22,37,-56,92,-133,210,-310,466,-696,1013,-1495,
%T A284628 2160,-3141,4495,-6462,9172,-13024,18387,-25840,36213,-50500,70280,
%U A284628 -97302,134522,-185105,254245,-347938,475036,-646676,878145,-1189468,1607095,-2166672,2913794
%N A284628 Expansion of Product_{k>=1} 1/(1+x^(2*k-1))^(2*k-1).
%H A284628 Seiichi Manyama, <a href="/A284628/b284628.txt">Table of n, a(n) for n = 0..10000</a>
%F A284628 a(n) = (-1)^n * A262811(n).
%t A284628 nmax = 50; CoefficientList[Series[Product[1/(1+x^(2*k-1))^(2*k-1), {k, 1, nmax}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Apr 15 2017 *)
%Y A284628 Cf. A255528, A262736, A262811.
%K A284628 sign
%O A284628 0,4
%A A284628 _Seiichi Manyama_, Apr 15 2017