A022052 - OEIS

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

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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