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A008431 Theta series of D_9 lattice. 2
1, 144, 2034, 7392, 22608, 44640, 93984, 141120, 262386, 343536, 557280, 703584, 1068384, 1234080, 1851264, 2057280, 2884176, 3231936, 4428242, 4639392, 6455520, 6670272, 8814816, 9320256 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 118.

LINKS

Table of n, a(n) for n=0..23.

FORMULA

Expansion of 1/2 (EllipticTheta(3, 0, q)^9 + EllipticTheta(4, 0, q)^9) (formula given by Mathematica's LatticeData(D9)) - Jean-François Alcover, Jul 07 2017

MATHEMATICA

terms = 24; s = 1/2 (EllipticTheta[3, 0, q]^9 + EllipticTheta[4, 0, q]^9) + O[q]^(2 terms); CoefficientList[s, q^2] (* Jean-François Alcover, Jul 07 2017 *)

CROSSREFS

Sequence in context: A223445 A186934 A066445 * A250084 A280025 A223687

Adjacent sequences:  A008428 A008429 A008430 * A008432 A008433 A008434

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified August 20 06:54 EDT 2018. Contains 313909 sequences. (Running on oeis4.)