A180820 Number of distinct solutions of sum{i=1..8}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 2..n-2.

0, 0, 0, 1, 5, 267, 3470, 43311, 345834, 2444098, 13182592, 64230756, 260084531, 976064810, 3209275269, 9963090038, 27970062442, 75278021479, 187003944842, 450006340740, 1014913338398, 2232744286681, 4653016292419, 9520091930911

Offset

1,5

Comments

Column 8 of A180823

Links

R. H. Hardin, Table of n, a(n) for n=1..183

Example

Solutions for sum of products of 8 2..3 pairs = 0 (mod 5) are
(2*2 + 2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 2*3)
(2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3)
(2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3)
(2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3)
(2*3 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3 + 3*3)

Crossrefs

Sequence in context: A175180 A238799 A113257 * A385941 A140001 A329610

Adjacent sequences: A180817 A180818 A180819 * A180821 A180822 A180823

Keyword

nonn

Author

R. H. Hardin, Sep 20 2010

Status

approved