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%I #4 Mar 31 2012 12:35:46
%S 0,20,429,5920,63954,510927,3362288,17975676,83628636,335900991,
%T 1222011613,3989760008,12105111844,33802351881,89361617169,
%U 221117356432,524533042878,1178959072101,2564070846089,5330170938874,10795501502457
%N Number of distinct solutions of sum{i=1..8}(x(2i-1)*x(2i)) = 1 (mod n), with x() in 0..n-1
%C Column 8 of A180813
%H R. H. Hardin, <a href="/A180810/b180810.txt">Table of n, a(n) for n=1..183</a>
%e Solutions for sum of products of 8 0..1 pairs = 1 (mod 2) are
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 1*1)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 0*1 + 0*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*1 + 0*1 + 0*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*0 + 1*1 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 0*0 + 0*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 0*1 + 0*1 + 0*1 + 0*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 0*1 + 0*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*0 + 1*1 + 1*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*1 + 0*1 + 0*1 + 0*1 + 0*1 + 1*1)
%e (0*0 + 0*0 + 0*1 + 0*1 + 0*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 0*0 + 0*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 0*1 + 0*1 + 0*1 + 0*1 + 0*1 + 0*1 + 1*1)
%e (0*0 + 0*1 + 0*1 + 0*1 + 0*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 0*1 + 0*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*1)
%e (0*0 + 1*1 + 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 + 1*1)
%e (0*1 + 0*1 + 0*1 + 0*1 + 0*1 + 1*1 + 1*1 + 1*1)
%e (0*1 + 0*1 + 0*1 + 1*1 + 1*1 + 1*1 + 1*1 + 1*1)
%e (0*1 + 1*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