%I #3 Mar 31 2012 12:35:46
%S 0,0,0,0,9,166,3474,36866,345458,2263066,13182593,61265760,260084494,
%T 944238967,3208593348,9709481260,27970062531,73672570068,187003944842,
%U 441746651920,1014700253185,2196105354893,4653016292528,9374868346319
%N Number of distinct solutions of sum{i=1..8}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 2..n-2
%C Column 8 of A180834
%H R. H. Hardin, <a href="/A180831/b180831.txt">Table of n, a(n) for n=1..183</a>
%e Solutions for sum of products of 8 2..3 pairs = 1 (mod 5) are
%e (2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*3 + 2*3)
%e (2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 3*3)
%e (2*2 + 2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 3*3 + 3*3)
%e (2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3)
%e (2*2 + 2*2 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3 + 3*3)
%e (2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3)
%e (2*2 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3 + 3*3 + 3*3)
%e (2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3)
%e (2*3 + 2*3 + 3*3 + 3*3 + 3*3 + 3*3 + 3*3 + 3*3)
%K nonn
%O 1,5
%A _R. H. Hardin_ Sep 20 2010