A180833 - OEIS

%I #3 Mar 31 2012 12:35:46

%S 0,0,0,0,11,403,13194,232088,3338772,34074527,290017026,1971610995,

%T 11651785754,58783446024,266722410390,1076378114380,4003448283079,

%U 13607830717566,43384915194505,128790677366846,363254278026186

%N Number of distinct solutions of sum{i=1..10}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 2..n-2

%C Column 10 of A180834

%H R. H. Hardin, <a href="/A180833/b180833.txt">Table of n, a(n) for n=1..183</a>

%e Solutions for sum of products of 10 2..3 pairs = 1 (mod 5) are

%e (2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3)

%e (2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 3*3)

%e (2*2 + 2*2 + 2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3)

%e (2*2 + 2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3)

%e (2*2 + 2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3 + 3*3)

%e (2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3)

%e (2*2 + 2*2 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3 + 3*3 + 3*3)

%e (2*2 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3)

%e (2*2 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3 + 3*3 + 3*3 + 3*3)

%e (2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 2*3 + 3*3 + 3*3)

%e (2*3 + 2*3 + 2*3 + 3*3 + 3*3 + 3*3 + 3*3 + 3*3 + 3*3 + 3*3)

%K nonn

%O 1,5

%A _R. H. Hardin_ Sep 20 2010