A180810 - OEIS

%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