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%I #3 Mar 31 2012 12:35:46
%S 0,0,9,198,2294,19467,126864,674922,2997717,11615754,39660995,
%T 123162204,348412638,920581314,2264397902,5294830516,11692554408,
%U 24858751383,50403391227,99282023930,187902783369,347689331443,621482071507
%N Number of distinct solutions of sum{i=1..7}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 1..n-1
%C Column 7 of A180782
%H R. H. Hardin, <a href="/A180778/b180778.txt">Table of n, a(n) for n=1..183</a>
%e Solutions for sum of products of 7 1..2 pairs = 0 (mod 3) are
%e (1*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*2 + 1*2)
%e (1*1 + 1*1 + 1*1 + 1*1 + 1*2 + 1*2 + 2*2)
%e (1*1 + 1*1 + 1*1 + 1*2 + 1*2 + 2*2 + 2*2)
%e (1*1 + 1*1 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2)
%e (1*1 + 1*1 + 1*2 + 1*2 + 2*2 + 2*2 + 2*2)
%e (1*1 + 1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 2*2)
%e (1*1 + 1*2 + 1*2 + 2*2 + 2*2 + 2*2 + 2*2)
%e (1*2 + 1*2 + 1*2 + 1*2 + 1*2 + 2*2 + 2*2)
%e (1*2 + 1*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*2)
%K nonn
%O 1,3
%A _R. H. Hardin_ Sep 20 2010
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