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A054907 Number of n-dimensional unimodular lattice (or quadratic forms) containing no vectors of norm 1. 4
1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 3, 1, 4, 3, 12, 12, 28, 49, 180, 368 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,17

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, A054908-A054909, A054911.

Sequence in context: A060043 A298254 A316402 * A245539 A089554 A276617

Adjacent sequences:  A054904 A054905 A054906 * A054908 A054909 A054910

KEYWORD

nonn,nice,hard

AUTHOR

N. J. A. Sloane, May 23 2000

STATUS

approved

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Last modified November 18 17:49 EST 2018. Contains 317323 sequences. (Running on oeis4.)