OFFSET
1,3
COMMENTS
Equivalently, of discriminant -4n^2.
LINKS
J. H. Conway and N. J. A. Sloane, Sphere Packings, Lattices and Groups, Springer-Verlag, 3rd edition, 1999, see Table 15.1.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Aug 11 2004
STATUS
approved