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 A289566 #19 Mar 05 2018 05:51:28
%S A289566 1,-120,20520,-3934560,793510440,-164694615120,34824089129760,
%T A289566 -7460017581785280,1613575314347164200,-351613291994820018840,
%U A289566 77073167391611232305520,-16975579813113940564868640,3753822590560913900129106720
%N A289566 Coefficients in expansion of 1/E_4^(1/2).
%H A289566 Seiichi Manyama, <a href="/A289566/b289566.txt">Table of n, a(n) for n = 0..423</a>
%F A289566 G.f.: Product_{n>=1} (1-q^n)^(-A110163(n)/2).
%F A289566 a(n) ~ (-1)^n * c * exp(Pi*sqrt(3)*n) / sqrt(n), where c = 3^(7/2) * Gamma(2/3)^9 / (2^(9/2) * Pi^(7/2)) = 0.5756695813762774104492155417156662666189119445257965... - _Vaclav Kotesovec_, Jul 09 2017, updated Mar 05 2018
%t A289566 nmax = 20; CoefficientList[Series[(1 + 240*Sum[DivisorSigma[3,k]*x^k, {k, 1, nmax}])^(-1/2), {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Jul 09 2017 *)
%Y A289566 1/E_k^(1/2): A289565 (k=2), this sequence (k=4), A289567 (k=6), A001943 (k=8), A289568 (k=10), A289569 (k=14).
%Y A289566 Cf. A001943 (1/E_4), A110163, A289292 (E_4^(1/2)).
%K A289566 sign
%O A289566 0,2
%A A289566 _Seiichi Manyama_, Jul 08 2017