A180789 - OEIS

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

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

OFFSET

1,3

COMMENTS

Column 7 of A180793

LINKS

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

EXAMPLE

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)

CROSSREFS

Sequence in context: A345445 A152587 A060337 * A078264 A322914 A014896

Adjacent sequences: A180786 A180787 A180788 * A180790 A180791 A180792

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 20 2010

STATUS

approved