A209003 Number of n-bead necklaces labeled with numbers -4..4 not allowing reversal, with sum zero and first and second differences in -4..4.

1, 2, 3, 10, 31, 153, 703, 3393, 16001, 75381, 357369, 1713043, 8299559, 40613618, 200412275, 995895544

Offset

1,2

Comments

Column 4 of A209007.

Links

Table of n, a(n) for n=1..16.

Example

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

Crossrefs

Sequence in context: A131764 A066706 A353052 * A080022 A192913 A364208

Adjacent sequences: A209000 A209001 A209002 * A209004 A209005 A209006

Keyword

nonn

Author

R. H. Hardin, Mar 04 2012

Status

approved