A208942 Number of n-bead necklaces labeled with numbers -5..5 not allowing reversal, with sum zero with no three beads in a row equal.

1, 6, 30, 223, 1722, 14430, 125322, 1123612, 10303798, 96228900, 911986784, 8749074498, 84797323618, 829080237870

Offset

1,2

Comments

Column 5 of A208945.

Links

Table of n, a(n) for n=1..14.

Example

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

Crossrefs

Sequence in context: A214822 A295497 A298457 * A209070 A259820 A126751

Adjacent sequences: A208939 A208940 A208941 * A208943 A208944 A208945

Keyword

nonn

Author

R. H. Hardin, Mar 03 2012

Status

approved