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 A290050 #11 Feb 26 2018 10:18:49
%S A290050 477481,-150101784,136249055208,-63604855321056,-195358116440088,
%T A290050 -7467654553124192784,-1717686223249005340128,
%U A290050 -153060438018813351348672,-7369907929791849766742040,-224318806535938497072194232,-4762271485690855450838091792
%N A290050 Coefficients in expansion of 691^2*E_6*E_12^2.
%H A290050 Seiichi Manyama, <a href="/A290050/b290050.txt">Table of n, a(n) for n = 0..1000</a>
%t A290050 terms = 11;
%t A290050 E6[x_] = 1 - 504*Sum[k^5*x^k/(1 - x^k), {k, 1, terms}];
%t A290050 E12[x_] = 1 + (65520/691)*Sum[k^11*x^k/(1 - x^k), {k, 1, terms}];
%t A290050 691^2*E6[x]*E12[x]^2 + O[x]^terms // CoefficientList[#, x]& (* _Jean-François Alcover_, Feb 26 2018 *)
%Y A290050 Cf. A013973 (E_6), A029828 (691*E_12).
%K A290050 sign
%O A290050 0,1
%A A290050 _Seiichi Manyama_, Jul 19 2017