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 A294181 #21 Jun 03 2018 07:55:43
%S A294181 1,-264,61128,-14107296,3255470952,-751247454384,173361309784992,
%T A294181 -40005651284526912,9231887649122522280,-2130392752758423726312,
%U A294181 491619206548389935051568,-113448303808924351510423008,26179851123971817380111236128
%N A294181 Coefficients in expansion of E_2/E_4.
%H A294181 Seiichi Manyama, <a href="/A294181/b294181.txt">Table of n, a(n) for n = 0..422</a>
%F A294181 Convolution inverse of A288877.
%F A294181 a(n) ~ (-1)^n * 1024 * Pi^11 * exp(Pi*sqrt(3)*n) / (3^(3/2) * Gamma(1/3)^18). - _Vaclav Kotesovec_, Jun 03 2018
%t A294181 terms = 13;
%t A294181 E2[x_] = 1 - 24*Sum[k*x^k/(1 - x^k), {k, 1, terms}];
%t A294181 E4[x_] = 1 + 240*Sum[k^3*x^k/(1 - x^k), {k, 1, terms}];
%t A294181 E2[x]/E4[x] + O[x]^terms // CoefficientList[#, x]& (* _Jean-François Alcover_, Feb 23 2018 *)
%Y A294181 Cf. A001943, A004009 (E_4), A006352 (E_2), A288877.
%Y A294181 E_k/E_{k+2}: this sequence (k=2), A294182 (k=4), A294183 (k=6).
%K A294181 sign
%O A294181 0,2
%A A294181 _Seiichi Manyama_, Feb 11 2018