A180789 Number of distinct solutions of sum{i=1..7}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 1..n-1.

0, 1, 15, 198, 2282, 19300, 126861, 670058, 2997685, 11539243, 39660969, 122371876, 348412793, 914595808, 2264326584, 5259342780, 11692554312, 24683815072, 50403390786, 98560661538, 187881799209, 345060981679, 621482071341

Offset: 1

Author

R. H. Hardin Sep 20 2010

Keywords

• nonn

Comments

Column 7 of A180793

Examples

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

Links

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