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 A015684 #12 Oct 23 2018 08:14:23
%S A015684 1,-7,63,-693,8841,-127575,2047815,-36081045,690863985,-14263534215,
%T A015684 315469515375,-7434244696725,185817177956025,-4906778826324375,
%U A015684 136422375634920375,-3981559981797523125,121659806332798358625
%N A015684 Expansion of e.g.f. theta_3^(-7/2).
%D A015684 J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 102.
%H A015684 Seiichi Manyama, <a href="/A015684/b015684.txt">Table of n, a(n) for n = 0..432</a>
%t A015684 nmax = 25; CoefficientList[Series[EllipticTheta[3, 0, x]^(-7/2), {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Oct 23 2018 *)
%K A015684 sign
%O A015684 0,2
%A A015684 _N. J. A. Sloane_