A022074 Theta series of D*_21 lattice.

1, 0, 0, 0, 42, 0, 0, 0, 840, 0, 0, 0, 10640, 0, 0, 0, 95802, 0, 0, 0, 652848, 2097152, 0, 0, 3504816, 0, 0, 0, 15266880, 44040192, 0, 0, 55350120, 0, 0, 0, 171361498, 440401920, 0, 0, 465944304, 0, 0, 0, 1145653488, 2833252352, 0, 0, 2610853840, 0, 0, 0

Offset

0,5

References

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 120.

Links

Andy Huchala, Table of n, a(n) for n = 0..1876

Example

G.f. = 1 + 42*q^4 + 840*q^8 + ...

Prog

(Magma)
L := Dual(Lattice("D", 21));
B := Basis(ThetaSeriesModularFormSpace(L), 60);
S := [1, 0, 0, 0, 42, 0, 0, 0, 840, 0, 0];
Coefficients(&+[B[i] * S[i] : i in [1..11]]); // Andy Huchala, Jul 14 2021

Crossrefs

Sequence in context: A095189 A023932 A243831 * A335188 A263303 A263288

Adjacent sequences: A022071 A022072 A022073 * A022075 A022076 A022077

Keyword

nonn

Author

N. J. A. Sloane

Extensions

More terms from Andy Huchala, Jul 14 2021

Status

approved