A015161 Theta series of 17-dimensional lattice Q_17(6)^{+6}.

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 240, 0, 0, 1020, 816, 0, 0, 2040, 0, 0, 0, 0, 17952, 0, 0, 34782, 20400, 0, 0, 41956, 0, 0, 0, 0, 208080, 0, 0, 376992, 236912, 0, 0, 362406, 0, 0, 0, 0, 1618944, 0, 0, 2306832, 1236240, 0, 0, 1933920, 0, 0, 0, 0, 6613680, 0, 0, 9891384, 5861328, 0, 0, 7591792, 0, 0, 0, 0, 26689728, 0, 0, 33439476, 17201280, 0, 0, 24124428, 0, 0, 0, 0, 69759840, 0, 0, 95442624, 55003296, 0, 0, 65640978, 0, 0, 0, 0, 204207264

Offset

0,18

Links

Table of n, a(n) for n=0..101.

J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices II: Subgroups of GL(n,Z), Proc. Royal Soc. London, A 419 (1988), 29-68.

Gheorghe Coserea, Gram matrix.

G. Nebe and N. J. A. Sloane, Home page for this lattice

W. Plesken, Finite Unimodular Groups of Prime Degree and Circulants, J. Algebra, vol. 97 (1985), pp. 286-312.

Prog

(PARI) \\ system("wget https://oeis.org/A015161/a015161.txt");
g = matconcat(read("a015161.txt")~);
seq(N, g, flag=0) = concat(1, 2*Vec(qfrep(g, N, flag)));
seq(80, g) \\ Gheorghe Coserea, Nov 28 2018
(PARI)
GramMatrix()={my(p=[17, -1, -1, -1, -7, -1, -7, 5, 5, 5, 5, -7, -1, -7, -1, -1, -1]); matrix(#p, #p, i, j, p[(i-j) %#p + 1])}
a(n)={if(n==0, 1, 2*qfrep(GramMatrix(), n, 0)[n])} \\ Andrew Howroyd, Nov 29 2018

Crossrefs

Cf. A015158, A015159, A015160, A015162, A015163, A015164, A015165.

Sequence in context: A221302 A072173 A282230 * A298833 A298621 A299587

Adjacent sequences: A015158 A015159 A015160 * A015162 A015163 A015164

Keyword

nonn

Author

N. J. A. Sloane

Extensions

More terms from Gheorghe Coserea, Nov 28 2018

Status

approved