OFFSET
0,4
REFERENCES
J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices I: Quadratic Forms of Small Determinant, Proc. Royal Soc. London, Series A, 418 (1988), 17-41.
J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 110.
LINKS
John Cannon, Table of n, a(n) for n = 0..10000
EXAMPLE
1 + 20*q^3 + 30*q^4 + 60*q^7 + 90*q^8 + 180*q^11 + 140*q^12 + 132*q^15 + ...
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 31 2007
STATUS
approved