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 A328128 #8 Feb 16 2025 08:33:58
%S A328128 1,8,80,896,10784,136448,1790720,24160256,333053504,4670325248,
%T A328128 66403043840,954931245056,13863783325184,202898094829568,
%U A328128 2989879597076480,44320135356317696,660370844304147584,9884176356444627968,148535796374189204480,2240105752104228970496
%N A328128 G.f.: K(4*sqrt(x)) / E(4*sqrt(x)), where E(), K() are complete elliptic integrals.
%C A328128 Convolution of A002894 and A188266.
%H A328128 Vaclav Kotesovec, <a href="/A328128/b328128.txt">Table of n, a(n) for n = 0..820</a>
%H A328128 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/CompleteEllipticIntegraloftheFirstKind.html">Complete Elliptic Integral of the First Kind</a>.
%H A328128 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/CompleteEllipticIntegraloftheSecondKind.html">Complete Elliptic Integral of the Second Kind</a>.
%F A328128 a(n) ~ 2^(4*n-1) / n.
%p A328128 seq(coeff(series(EllipticK(4*sqrt(x))/EllipticE(4*sqrt(x)), x, 21), x, n), n = 0..20);
%t A328128 CoefficientList[Series[EllipticK[16*x]/EllipticE[16*x], {x, 0, 20}], x]
%Y A328128 Cf. A002894, A188266, A261976, A328127.
%K A328128 nonn
%O A328128 0,2
%A A328128 _Vaclav Kotesovec_, Oct 04 2019