A180824 - OEIS

%I #6 Mar 25 2023 22:24:24

%S 0,0,0,0,1,0,2,2,2,1,4,2,5,2,4,4,7,2,8,4,6,4,10,6,9,5,8,6,13,4,14,8,

%T 10,7,12,6,17,8,12,10,19,6,20,10,12,10,22,10,20,9,16,12,25,8,20,14,18,

%U 13,28,10,29,14,18,16,24,10,32,16,22,12,34,14,35,17,20,18,30,12,38,18,26,19,40

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

%C Column 1 of A180834.

%H R. H. Hardin, <a href="/A180824/b180824.txt">Table of n, a(n) for n=1..10000</a>

%Y Cf. A180834.

%K nonn

%O 1,7

%A _R. H. Hardin_, Sep 20 2010