A208990 Number of n-bead necklaces labeled with numbers -5..5 not allowing reversal, with sum zero and first differences in -5..5.

1, 3, 11, 58, 351, 2354, 16307, 116183, 843779, 6227718, 46571177, 352155364, 2688196663, 20688930990, 160363122189

Offset

1,2

Comments

Column 5 of A208993.

Links

Table of n, a(n) for n=1..15.

Example

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

Crossrefs

Sequence in context: A126201 A261643 A229512 * A020012 A126100 A009444

Adjacent sequences: A208987 A208988 A208989 * A208991 A208992 A208993

Keyword

nonn

Author

R. H. Hardin, Mar 04 2012

Status

approved