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A023906 Theta series of A_15 lattice. 1
1, 240, 10920, 163520, 1075860, 4464096, 14909440, 40080000, 96643950, 204728400, 412819680, 754303680, 1350075720, 2236728480, 3673313280, 5666507392, 8760753540, 12779981760, 18827053960, 26351976000, 37332319752, 50483661760, 69411962880, 91160284800, 122167955000 (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. 110.

LINKS

Table of n, a(n) for n=0..24.

G. Nebe and N. J. A. Sloane, Home page for this lattice

EXAMPLE

1 + 240*q^2 + 10920*q^4 + 163520*q^6 + 1075860*q^8 + 4464096*q^10 + 14909440*q^12 + 40080000*q^14 + O(q^15)

MATHEMATICA

terms = 20; f[q_] = LatticeData["A15", "ThetaSeriesFunction"][-I Log[q]/Pi]; s = Series[f[q], {q, 0, 2 terms}]; CoefficientList[s, q^2][[1 ;; terms]] // Round (* Jean-Fran├žois Alcover, Jul 07 2017 *)

CROSSREFS

Cf. A023927 (dual).

Sequence in context: A282227 A268902 A232994 * A292883 A292075 A035841

Adjacent sequences:  A023903 A023904 A023905 * A023907 A023908 A023909

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Robert.Harley(AT)inria.fr, see A023902.

More terms from Sean A. Irvine, Jun 12 2019

STATUS

approved

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Last modified January 17 17:47 EST 2022. Contains 350402 sequences. (Running on oeis4.)