A180830 Number of distinct solutions of sum{i=1..7}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 2..n-2

0, 0, 0, 0, 4, 98, 1634, 13191, 98721, 509796, 2452572, 9324188, 33559304, 102516038, 302010701, 786309831, 1997861579, 4607230060, 10461759080, 21941200490, 45604744028, 88621893721, 171539771106, 313255557883, 571763758062

Offset

1,5

Comments

Column 7 of A180834

Links

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

Example

Solutions for sum of products of 7 2..3 pairs = 1 (mod 5) are
(2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 2*3)
(2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3)
(2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3)
(2*3 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3)

Crossrefs

Sequence in context: A024384 A368004 A320358 * A361883 A265721 A224475

Adjacent sequences: A180827 A180828 A180829 * A180831 A180832 A180833

Keyword

nonn

Author

R. H. Hardin Sep 20 2010

Status

approved