A023906 Theta series of A_15 lattice.

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

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-François 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