%I #13 Oct 23 2018 08:15:09
%S 1,-21,483,-12075,325521,-9396765,288749475,-9398322675,322652227905,
%T -11641352627205,440043353374275,-17378800976950875,
%U 715361536295492625,-30625157300600587725,1360947531581394631875,-62670194480910433291875
%N Expansion of e.g.f. theta_3^(-21/2).
%D J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 102.
%H Seiichi Manyama, <a href="/A015695/b015695.txt">Table of n, a(n) for n = 0..419</a>
%t nmax = 25; CoefficientList[Series[EllipticTheta[3, 0, x]^(-21/2), {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Oct 23 2018 *)
%K sign
%O 0,2
%A _N. J. A. Sloane_