A208940 Number of n-bead necklaces labeled with numbers -3..3 not allowing reversal, with sum zero with no three beads in a row equal.

1, 4, 12, 57, 274, 1464, 7974, 45050, 260046, 1529746, 9129838, 55159410, 336661016, 2072786142, 12858170994, 80288297320, 504231724034

Offset

1,2

Comments

Column 3 of A208945.

Links

Table of n, a(n) for n=1..17.

Example

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

Crossrefs

Sequence in context: A144012 A197924 A065125 * A209068 A177265 A243923

Adjacent sequences: A208937 A208938 A208939 * A208941 A208942 A208943

Keyword

nonn

Author

R. H. Hardin, Mar 03 2012

Status

approved