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A005134 Number of n-dimensional unimodular lattice (or quadratic forms).
(Formerly M0219)
4
1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 4, 5, 8, 9, 13, 16, 28, 40, 68, 117, 297, 665 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,9

REFERENCES

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

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

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

CROSSREFS

Cf. A054907-A054909, A054911.

Sequence in context: A249040 A153683 A005139 * A081651 A029193 A005858

Adjacent sequences:  A005131 A005132 A005133 * A005135 A005136 A005137

KEYWORD

nonn,nice,hard

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified November 27 16:30 EST 2014. Contains 250240 sequences.