A208824 Number of n-bead necklaces labeled with numbers -7..7 allowing reversal, with sum zero.

1, 8, 32, 316, 3085, 35288, 417204, 5134796, 64630243, 829140440, 10794728782, 142275197892, 1894548608563

Offset: 1

Author

R. H. Hardin, Mar 01 2012

Keywords

• nonn

Comments

Column 7 of A208825.

Examples

			Some solutions for n=3:
.-3...-3....0...-5...-2...-5...-7...-6...-4...-6...-4...-6...-3...-7...-2...-7
..0...-3....0....2....0....0....0....1...-3...-1...-2....3...-1....3...-2....2
..3....6....0....3....2....5....7....5....7....7....6....3....4....4....4....5