OFFSET
0,2
REFERENCES
J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 120.
LINKS
Andy Huchala, Table of n, a(n) for n = 0..20000
G. Nebe and N. J. A. Sloane, Home page for this lattice
FORMULA
Empirical: Sum_{n>=0} a(n) / exp(n*Pi) = (9/8) * Pi^3 / Gamma(3/4)^12 = A388243. - Simon Plouffe, Sep 15 2025
EXAMPLE
G.f. = 1 + 24*q^2 + 264*q^4 + ...
PROG
(SageMath)
L = [1, 24]
M = ModularForms(Gamma0(2), 6)
bases = [_.q_expansion(20) for _ in M.integral_basis()]
f = sum(x*y for (x, y) in zip(bases, L)); list(f) # Andy Huchala, Jul 13 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved
