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 A303439 #11 Apr 25 2018 06:50:43
%S A303439 1,-2,0,-2,6,-6,4,-6,48,-118,96,-78,470,-810,396,-3050,11062,-12678,
%T A303439 7072,-21454,80034,-201490,218940,-200658,1536724,-3268842,2079312,
%U A303439 -7013266,23140282,-28227510,24133668,-56293910,288065712,-704485126,629862288,-1176210654
%N A303439 Expansion of Product_{k>=1} ((1 - 2^k*x^k)/(1 + 2^k*x^k))^(1/2^k).
%H A303439 Seiichi Manyama, <a href="/A303439/b303439.txt">Table of n, a(n) for n = 0..3000</a>
%t A303439 nmax = 30; CoefficientList[Series[Exp[Sum[(1 - (-1)^j) / (j*(1 - 1/(2^(j-1)*x^j))), {j, 1, nmax}]], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Apr 25 2018 *)
%o A303439 (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, ((1-2^k*x^k)/(1+2^k*x^k))^(1/2^k)))
%Y A303439 Cf. A303345, A303387, A303396, A303438.
%K A303439 sign
%O A303439 0,2
%A A303439 _Seiichi Manyama_, Apr 24 2018