A008447 - OEIS

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A008447

Theta series of A_7 lattice.

1, 56, 420, 896, 2366, 3360, 6440, 7168, 14196, 14168, 22120, 24192, 37912, 33824, 55440, 50176, 75838, 71232, 98700, 88704, 141960, 117824, 156520, 150528, 217672, 173656, 261240, 218624, 303424, 273504, 355600, 301056, 455028, 359744, 474320

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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..34.

MATHEMATICA

terms = 29; f[q_] = LatticeData["A7", "ThetaSeriesFunction"][-I Log[q]/Pi]; s = Series[f[q], {q, 0, 2 terms}]; DeleteCases[CoefficientList[s, q^(1/2) ] // Round, 0][[1 ;; terms]] (* Jean-François Alcover, Jul 04 2017 *)

PROG

(Magma) L:=Lattice("A", 7); T1<q> := ThetaSeries(L, 60);

CROSSREFS

Cf. A023919 (dual).

Sequence in context: A075283 A205313 A287702 * A076647 A187159 A220048

Adjacent sequences: A008444 A008445 A008446 * A008448 A008449 A008450

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Sean A. Irvine, Jun 12 2019

STATUS

approved