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A023909 Theta series of A_18 lattice. 1
1, 342, 23256, 548454, 5756202, 33953760, 145404264, 501480756, 1455087222, 3744992834, 8666394912, 18652602708, 37257431778, 70992509796, 127919023344, 222954244860, 372270931974, 606984681420, 955026275808, 1477806578172, 2218909983696, 3290673763164 (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..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-Fran├žois 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

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Last modified January 27 19:29 EST 2022. Contains 350611 sequences. (Running on oeis4.)