A022052 Theta series of D_21 lattice.

1, 840, 95802, 3504816, 55350120, 465944304, 2610853840, 11337146784, 40208417466, 123411903160, 335056780464, 830096613360, 1893781702512, 4058779021584, 8190877926720, 15805879161632, 29122237029480, 51905458442208, 89163973663338, 149313692762640, 242598110651568

Offset

0,2

References

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 118.

Links

Seiichi Manyama, Table of n, a(n) for n = 0..1000

Mathematica

terms = 17; f[q_] = LatticeData["D21", "ThetaSeriesFunction"][-I*Log[q]/Pi]; s = f[q] + O[q]^(2 terms); DeleteCases[CoefficientList[s, q], 0][[1 ;; terms]] (* Jean-François Alcover, Jul 06 2017 *)

Crossrefs

Sequence in context: A166764 A226268 A218410 * A055353 A107516 A091035

Adjacent sequences: A022049 A022050 A022051 * A022053 A022054 A022055

Keyword

nonn,easy

Author

N. J. A. Sloane

Extensions

More terms from Seiichi Manyama, Oct 16 2018

Status

approved