A209112 Number of n-bead necklaces labeled with numbers -5..5 not allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.

1, 6, 29, 221, 1683, 14037, 121117, 1079992, 9849223, 91488850, 862442967, 8230097726, 79348933361

Offset

1,2

Comments

Column 5 of A209115.

Links

Table of n, a(n) for n=1..13.

Example

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

Crossrefs

Sequence in context: A020036 A294312 A054748 * A205811 A143563 A266205

Adjacent sequences: A209109 A209110 A209111 * A209113 A209114 A209115

Keyword

nonn

Author

R. H. Hardin, Mar 05 2012

Status

approved