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 A303347 #18 Apr 25 2018 04:00:30
%S A303347 1,-2,-4,-2,-6,-6,-56,-158,-612,-2070,-7228,-25238,-89646,-319466,
%T A303347 -1150168,-4164978,-15177718,-55592614,-204617788,-756314982,
%U A303347 -2806456898,-10450497682,-39040372248,-146273912858,-549533738952,-2069680656234,-7812908945556
%N A303347 Expansion of Product_{n>=1} (1 - 4*x^n)^(1/2).
%C A303347 This sequence is obtained from the generalized Euler transform in A266964 by taking f(n) = -1/2, g(n) = 4.
%H A303347 Seiichi Manyama, <a href="/A303347/b303347.txt">Table of n, a(n) for n = 0..1000</a>
%F A303347 a(n) ~ -c * 2^(2*n-1) / (sqrt(Pi) * n^(3/2)), where c = QPochhammer[1/4]^(1/2) = 0.8297816201389011939293261374110190... - _Vaclav Kotesovec_, Apr 25 2018
%p A303347 seq(coeff(series(mul((1-4*x^k)^(1/2), k = 1..n), x, n+1), x, n), n=0..40); # _Muniru A Asiru_, Apr 22 2018
%o A303347 (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, (1-4*x^k)^(1/2)))
%Y A303347 Expansion of Product_{n>=1} (1 - b^2*x^n)^(1/b): A010815 (b=1), this sequence (b=2), A303348 (b=3).
%Y A303347 Cf. A067855, A303350.
%K A303347 sign
%O A303347 0,2
%A A303347 _Seiichi Manyama_, Apr 22 2018