A180827 Number of distinct solutions of sum{i=1..4}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 2..n-2

0, 0, 0, 0, 5, 13, 103, 302, 1182, 2676, 7472, 14368, 32620, 55157, 110783, 172932, 315241, 457366, 783739, 1088297, 1750273, 2335589, 3624725, 4656872, 6991039, 8758150, 12682152, 15651854, 22182704, 26463796, 37062084, 43858102, 59401343

Offset

1,5

Comments

Column 4 of A180834

Links

R. H. Hardin, Table of n, a(n) for n=1..376

Example

Solutions for sum of products of 4 2..4 pairs = 1 (mod 6) are
(2*2 + 2*2 + 2*4 + 3*3) (2*2 + 2*3 + 2*3 + 3*3) (2*2 + 2*3 + 3*3 + 3*4)
(2*2 + 2*4 + 3*3 + 4*4) (2*2 + 3*3 + 3*3 + 3*3) (2*2 + 3*3 + 3*4 + 3*4)
(2*3 + 2*3 + 3*3 + 4*4) (2*3 + 2*4 + 2*4 + 3*3) (2*3 + 3*3 + 3*4 + 4*4)
(2*4 + 2*4 + 3*3 + 3*4) (2*4 + 3*3 + 4*4 + 4*4) (3*3 + 3*3 + 3*3 + 4*4)
(3*3 + 3*4 + 3*4 + 4*4)

Crossrefs

Sequence in context: A117340 A304348 A305912 * A117437 A179089 A106046

Adjacent sequences: A180824 A180825 A180826 * A180828 A180829 A180830

Keyword

nonn

Author

R. H. Hardin Sep 20 2010

Status

approved