%I #4 Mar 31 2012 12:35:46
%S 0,30,1001,22696,392250,4972016,49761505,397307654,2659084116,
%T 15109820870,75357373680,332792786617,1331562266837,4853931902522,
%U 16394137405008,51451948421640,152009675134746,423289393214764
%N Number of distinct solutions of sum{i=1..10}(x(2i-1)*x(2i)) = 1 (mod n), with x() in 0..n-1
%C Column 10 of A180813
%H R. H. Hardin, <a href="/A180812/b180812.txt">Table of n, a(n) for n=1..183</a>
%K nonn
%O 1,2
%A _R. H. Hardin_, suggested by _Max Alekseyev_ in the Sequence Fans Mailing List, Sep 20 2010