A180820 - OEIS

%I #3 Mar 31 2012 12:35:46

%S 0,0,0,1,5,267,3470,43311,345834,2444098,13182592,64230756,260084531,

%T 976064810,3209275269,9963090038,27970062442,75278021479,187003944842,

%U 450006340740,1014913338398,2232744286681,4653016292419,9520091930911

%N Number of distinct solutions of sum{i=1..8}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 2..n-2

%C Column 8 of A180823

%H R. H. Hardin, <a href="/A180820/b180820.txt">Table of n, a(n) for n=1..183</a>

%e Solutions for sum of products of 8 2..3 pairs = 0 (mod 5) are

%e (2*2 + 2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 2*3)

%e (2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3)

%e (2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3)

%e (2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3)

%e (2*3 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3 + 3*3)

%K nonn

%O 1,5

%A _R. H. Hardin_ Sep 20 2010