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%I #4 Mar 31 2012 12:35:46
%S 1,20,270,3000,23282,151473,768541,3422978,12879078,44111410,
%T 133919379,381516366,988173838,2446846672,5633359713,12527643860,
%U 26226659375,53655084387,104124710377,198817175068,363133886202,654527617329
%N Number of distinct solutions of sum{i=1..7}(x(2i-1)*x(2i)) = 0 (mod n), with x() in 0..n-1
%C Column 7 of A180803
%H R. H. Hardin, <a href="/A180799/b180799.txt">Table of n, a(n) for n=1..183</a>
%e Solutions for sum of products of 7 0..1 pairs = 0 (mod 2) are
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*0)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*1)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*1 + 0*1)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*1 + 0*1 + 0*1)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*1 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 0*1 + 0*1 + 0*1 + 0*1)
%e (0*0 + 0*0 + 0*0 + 0*1 + 0*1 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 1*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*1 + 0*1 + 0*1 + 0*1 + 0*1)
%e (0*0 + 0*0 + 0*1 + 0*1 + 0*1 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*1 + 1*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 0*1 + 0*1 + 0*1 + 0*1 + 0*1 + 0*1)
%e (0*0 + 0*1 + 0*1 + 0*1 + 0*1 + 1*1 + 1*1)
%e (0*0 + 0*1 + 0*1 + 1*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 1*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*1)
%e (0*1 + 0*1 + 0*1 + 0*1 + 0*1 + 0*1 + 0*1)
%e (0*1 + 0*1 + 0*1 + 0*1 + 0*1 + 1*1 + 1*1)
%e (0*1 + 0*1 + 0*1 + 1*1 + 1*1 + 1*1 + 1*1)
%e (0*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*1)
%K nonn
%O 1,2
%A _R. H. Hardin_, suggested by _Max Alekseyev_ in the Sequence Fans Mailing List, Sep 20 2010
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