A023909 Theta series of A_18 lattice.

1, 342, 23256, 548454, 5756202, 33953760, 145404264, 501480756, 1455087222, 3744992834, 8666394912, 18652602708, 37257431778, 70992509796, 127919023344, 222954244860, 372270931974, 606984681420, 955026275808, 1477806578172, 2218909983696, 3290673763164

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..21.

Mathematica

terms = 18; f[q_] = LatticeData["A18", "ThetaSeriesFunction"][-I*Log[q]/Pi]; s = f[q] + O[q]^(2 terms); Partition[CoefficientList[s, q] // Round, 2][[All, 1]][[1 ;; terms]] (* Jean-François Alcover, Jul 06 2017 *)

Crossrefs

Sequence in context: A231267 A252235 A272380 * A035844 A028681 A005072

Adjacent sequences: A023906 A023907 A023908 * A023910 A023911 A023912

Keyword

nonn

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