OFFSET
0,3
REFERENCES
J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 120.
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..10000 (terms 0..2500 from G. C. Greubel)
FORMULA
G.f.: (theta2(q)^20 + theta3(q)^20 + theta4(q)^20)/2.
MATHEMATICA
terms = 21; s = 1/2 (EllipticTheta[2, 0, q]^20 + EllipticTheta[3, 0, q]^20 + EllipticTheta[4, 0, q]^20) + O[q]^terms; CoefficientList[s, q] (* Jean-François Alcover, Jul 07 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved