A180778 - OEIS

A180778

Number of distinct solutions of sum{i=1..7}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 1..n-1

0, 0, 9, 198, 2294, 19467, 126864, 674922, 2997717, 11615754, 39660995, 123162204, 348412638, 920581314, 2264397902, 5294830516, 11692554408, 24858751383, 50403391227, 99282023930, 187902783369, 347689331443, 621482071507

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

COMMENTS

Column 7 of A180782

LINKS

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

EXAMPLE

Solutions for sum of products of 7 1..2 pairs = 0 (mod 3) are

(1*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*2 + 1*2)

(1*1 + 1*1 + 1*1 + 1*1 + 1*2 + 1*2 + 2*2)

(1*1 + 1*1 + 1*1 + 1*2 + 1*2 + 2*2 + 2*2)

(1*1 + 1*1 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2)

(1*1 + 1*1 + 1*2 + 1*2 + 2*2 + 2*2 + 2*2)

(1*1 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 2*2)

(1*1 + 1*2 + 1*2 + 2*2 + 2*2 + 2*2 + 2*2)

(1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 2*2 + 2*2)

(1*2 + 1*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*2)

CROSSREFS

Sequence in context: A274269 A250401 A291974 * A110807 A019566 A338226

Adjacent sequences: A180775 A180776 A180777 * A180779 A180780 A180781

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 20 2010

STATUS

approved