

A008431


Theta series of D_9 lattice.


1



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", SpringerVerlag, 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))  JeanFrançois 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] (* JeanFrançois 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



