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Number of distinct solutions of sum{i=1..3}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 2..n-2
1

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

%S 0,0,0,1,0,15,32,111,210,497,768,1751,2233,4209,5869,9758,11636,20111,

%T 22526,36545,42994,60736,67992,108343,111052,156047,179695,243023,

%U 250355,372867,362192,506374,545558,685635,723637,1023180,952948,1253394

%N Number of distinct solutions of sum{i=1..3}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 2..n-2

%C Column 3 of A180823

%H R. H. Hardin, <a href="/A180815/b180815.txt">Table of n, a(n) for n=1..444</a>

%e Solutions for sum of products of 3 2..4 pairs = 0 (mod 6) are

%e (2*2 + 2*2 + 2*2) (2*2 + 2*2 + 4*4) (2*2 + 2*3 + 2*4) (2*2 + 2*4 + 3*4)

%e (2*2 + 4*4 + 4*4) (2*3 + 2*3 + 2*3) (2*3 + 2*3 + 3*4) (2*3 + 2*4 + 4*4)

%e (2*3 + 3*3 + 3*3) (2*3 + 3*4 + 3*4) (2*4 + 2*4 + 2*4) (2*4 + 3*4 + 4*4)

%e (3*3 + 3*3 + 3*4) (3*4 + 3*4 + 3*4) (4*4 + 4*4 + 4*4)

%K nonn

%O 1,6

%A _R. H. Hardin_ Sep 20 2010