A180825 Number of distinct solutions of sum{i=1..2}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 2..n-2

0, 0, 0, 0, 0, 2, 8, 8, 25, 27, 58, 58, 115, 112, 193, 194, 324, 266, 485, 428, 652, 596, 958, 770, 1270, 1069, 1543, 1402, 2121, 1552, 2657, 2246, 3008, 2659, 3893, 2986, 4780, 3846, 5193, 4562, 6693, 4782, 7814, 6298, 8055, 7188, 10423, 7682, 11837, 9151

Offset

1,6

Comments

Column 2 of A180834

Links

R. H. Hardin, Table of n, a(n) for n=1..999

Example

Solutions for sum of products of 2 2..7 pairs = 1 (mod 9) are
(2*2 + 2*3) (2*2 + 3*5) (2*2 + 4*6) (2*2 + 6*7) (2*3 + 7*7) (2*4 + 4*5)
(2*5 + 3*3) (2*5 + 3*6) (2*5 + 6*6) (2*6 + 4*4) (2*6 + 5*5) (2*7 + 2*7)
(3*3 + 4*7) (3*4 + 4*4) (3*4 + 5*5) (3*5 + 7*7) (3*6 + 4*7) (3*7 + 4*4)
(3*7 + 5*5) (4*4 + 5*6) (4*5 + 5*7) (4*6 + 7*7) (4*7 + 6*6) (5*5 + 5*6)
(6*7 + 7*7)

Crossrefs

Sequence in context: A375853 A146749 A250313 * A230708 A230739 A227326

Adjacent sequences: A180822 A180823 A180824 * A180826 A180827 A180828

Keyword

nonn

Author

R. H. Hardin Sep 20 2010

Status

approved