A054908 Number of n-dimensional odd unimodular lattice (or quadratic forms) containing no vectors of norm 1.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 4, 3, 12, 12, 28, 49, 156, 368

Offset

0,19

References

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 49.

Links

Table of n, a(n) for n=0..25.

Crossrefs

Cf. A005134, A054907-A054909, A054911.

Sequence in context: A272220 A231427 A215942 * A141826 A178756 A271696

Adjacent sequences: A054905 A054906 A054907 * A054909 A054910 A054911

Keyword

nonn,nice,more,hard

Author

N. J. A. Sloane, May 23 2000

Status

approved