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%I #6 Mar 31 2012 12:36:16
%S 1,8,63,1246,31284,839968,26586582,1012894742,43952718714,
%T 2154085255777,116337778510833,6974910796570573,453756196177752909,
%U 32037319291934188145,2433852671789915900894,198648198467160364716000
%N 1/4 the number of arrangements of n+1 nonzero numbers x(i) in -n..n with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero
%C Diagonal of A189951
%H R. H. Hardin, <a href="/A189943/b189943.txt">Table of n, a(n) for n = 1..18</a>
%e Some solutions with n=3
%e .-2...-3...-2...-2....3....3...-2....1...-1....2...-3...-2...-3...-1....1....3
%e .-1....1...-1....1...-2...-2....2...-2....2....1....3....2....1....1....1....2
%e ..1...-3....3...-1...-1....3....2...-1...-3...-3...-3...-2....1....1...-1...-1
%e .-1....2...-2....1...-3....2...-2...-2...-2...-2....1...-2...-1...-1...-1....2
%K nonn
%O 1,2
%A _R. H. Hardin_ May 02 2011
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