login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A015163 Theta series of 17-dimensional lattice Q'_17(6)^{+2}. 8
1, 0, 0, 136, 1326, 8160, 31552, 88128, 240618, 658784, 1452480, 2622216, 5030028, 10390944, 18128256, 26822464, 43527174, 77769696, 119299200, 157895592, 232127928, 379052672, 537564480, 662425536, 910537442, 1402281312, 1881950592, 2201578336, 2894860164, 4268628192, 5501926784 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..30.

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/A015163/a015163.txt");

g = matconcat(read("a015163.txt")~);

seq(N, g, flag=0) = concat(1, 2*Vec(qfrep(g, N, flag)));

seq(15, g) \\ Gheorghe Coserea, Nov 28 2018

(PARI)

GramMatrix()={my(p=[3, -1, 0, 0, 1, -1, 0, 1, 0, 0, 1, 0, -1, 1, 0, 0, -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, A015161, A015162, A015164, A015165.

Sequence in context: A251175 A251168 A023070 * A235190 A249985 A072897

Adjacent sequences:  A015160 A015161 A015162 * A015164 A015165 A015166

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Gheorghe Coserea, Nov 28 2018

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 29 21:48 EDT 2022. Contains 354913 sequences. (Running on oeis4.)