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A180776 Number of distinct solutions of sum{i=1..5}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 1..n-1 1

%I

%S 0,0,7,62,402,1960,7587,25470,73146,193036,455161,1022770,2098782,

%T 4196208,7797217,14286908,24527232,42125055,67955391,110571248,

%U 170260213,264585538,390623343,588725404,837466268,1220597598,1696535256

%N Number of distinct solutions of sum{i=1..5}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 1..n-1

%C Column 5 of A180782

%H R. H. Hardin, <a href="/A180776/b180776.txt">Table of n, a(n) for n=1..249</a>

%e Solutions for sum of products of 5 1..2 pairs = 0 (mod 3) are

%e (1*1 + 1*1 + 1*1 + 1*1 + 1*2) (1*1 + 1*1 + 1*1 + 1*2 + 2*2)

%e (1*1 + 1*1 + 1*2 + 2*2 + 2*2) (1*1 + 1*2 + 1*2 + 1*2 + 1*2)

%e (1*1 + 1*2 + 2*2 + 2*2 + 2*2) (1*2 + 1*2 + 1*2 + 1*2 + 2*2)

%e (1*2 + 2*2 + 2*2 + 2*2 + 2*2)

%K nonn

%O 1,3

%A _R. H. Hardin_ Sep 20 2010

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Last modified May 16 18:41 EDT 2022. Contains 353720 sequences. (Running on oeis4.)