A180815 Number of distinct solutions of sum{i=1..3}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 2..n-2

0, 0, 0, 1, 0, 15, 32, 111, 210, 497, 768, 1751, 2233, 4209, 5869, 9758, 11636, 20111, 22526, 36545, 42994, 60736, 67992, 108343, 111052, 156047, 179695, 243023, 250355, 372867, 362192, 506374, 545558, 685635, 723637, 1023180, 952948, 1253394

Offset

1,6

Comments

Column 3 of A180823

Links

R. H. Hardin, Table of n, a(n) for n=1..444

Example

Solutions for sum of products of 3 2..4 pairs = 0 (mod 6) are
(2*2 + 2*2 + 2*2) (2*2 + 2*2 + 4*4) (2*2 + 2*3 + 2*4) (2*2 + 2*4 + 3*4)
(2*2 + 4*4 + 4*4) (2*3 + 2*3 + 2*3) (2*3 + 2*3 + 3*4) (2*3 + 2*4 + 4*4)
(2*3 + 3*3 + 3*3) (2*3 + 3*4 + 3*4) (2*4 + 2*4 + 2*4) (2*4 + 3*4 + 4*4)
(3*3 + 3*3 + 3*4) (3*4 + 3*4 + 3*4) (4*4 + 4*4 + 4*4)

Crossrefs

Sequence in context: A007256 A199743 A331551 * A336625 A177204 A342193

Adjacent sequences: A180812 A180813 A180814 * A180816 A180817 A180818

Keyword

nonn

Author

R. H. Hardin Sep 20 2010

Status

approved