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%I #4 Mar 31 2012 12:36:12
%S 4671,173409,1763151,10396729,40629247,136061137,355442823,870473329,
%T 1876439327,3821007601,7047842559
%N Number of arrangements of 9 numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero
%C Row 8 of A188358
%e Some solutions for n=4
%e .-4...-3...-3...-3...-4...-3...-4...-4...-3...-3...-4...-4...-3...-4...-3...-3
%e .-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4...-4
%e ..0....0....1....1...-4....0....2...-1....0...-4...-1....2....1....1....1....1
%e .-1...-4...-1...-4...-3...-1...-2....3....3....4....4...-2....1....1...-1....1
%e ..3...-3...-1....2....4....4...-1...-4...-4...-2...-3....2...-3...-3...-2...-3
%e .-2....2....2....4...-4...-4...-2....1...-1....2....0...-2....4...-2....1....4
%e ..2...-3...-4....0....4...-3....2....3....1...-1...-1....0....0...-4....2....0
%e .-3....4...-1....2....2....4...-4....4...-3....2....2....1....2....3...-3....3
%e .-1....0....2...-2...-4....2...-1...-4....0....2...-1....4....3...-4....1....2
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 28 2011
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