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 A261975 #11 Apr 10 2018 11:23:32
%S A261975 1,-8,48,-224,864,-2928,9024,-25792,69312,-176936,432288,-1016736,
%T A261975 2312832,-5107504,10983552,-23060544,47373696,-95401872,188637936,
%U A261975 -366744160,701930304,-1324016896,2463662016,-4526174784,8216376576,-14747939768,26191413024,-46048199360
%N A261975 Expansion of elliptic_E / elliptic_K in powers of q.
%H A261975 Vaclav Kotesovec, <a href="/A261975/b261975.txt">Table of n, a(n) for n = 0..10000</a>
%F A261975 G.f.: (T4^4 * T3 + 4*q * d/dq T3) / T3^5 where T3 = theta_3(q) and T4 = theta_4(q).
%t A261975 nmax = 30; dtheta = D[Normal[Series[EllipticTheta[3, 0, x], {x, 0, nmax}]], x]; CoefficientList[Series[(EllipticTheta[4, 0, x]^4*EllipticTheta[3, 0, x] + 4*x*dtheta)/EllipticTheta[3, 0, x]^5, {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Apr 10 2018 *)
%Y A261975 Cf. A004018 (elliptic K(q)), A194094 (elliptic E(q)), A115977 (elliptic k(q)^2).
%Y A261975 Cf. A261975 (E/K), A261977 ((E/K)^(1/2)), A261978 ((E/K)^(1/4)).
%Y A261975 Cf. A261976 (K/E), A261979 ((K/E)^(1/2)), A261980 ((K/E)^(1/4)).
%K A261975 sign
%O A261975 0,2
%A A261975 _Joerg Arndt_, Sep 07 2015