%I #7 Mar 13 2017 00:18:33
%S 1,2,5,33,351,5404,104001,2416967,65820325,2058166065,72731671225
%N Number of n-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and first differences in -n..n.
%C Diagonal of A208993.
%e Some solutions for n=6:
%e .-3...-5...-3...-4...-5...-5...-4...-3...-4...-1...-5...-4...-3...-4...-5...-3
%e .-3....1....2....1...-5....1....2....0....1...-1....0....2....1...-1....0...-1
%e ..2...-1....1...-1...-1....5....2...-2...-2...-1....5...-1....2....2...-1....0
%e ..0....2...-2....3....4....2...-2....1....3....3....0....3....0...-1....5....6
%e ..5....3....1....1....6....1....3....1....4....0....2....3....0....2....0....0
%e .-1....0....1....0....1...-4...-1....3...-2....0...-2...-3....0....2....1...-2
%K nonn
%O 1,2
%A _R. H. Hardin_, Mar 04 2012