A209484 Number of n-bead necklaces labeled with numbers -7..7 allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.

1, 8, 31, 311, 3014, 34233, 401634, 4907310, 61316012, 780896062, 10092511209

Offset

1,2

Comments

Column 7 of A209485.

Links

Table of n, a(n) for n=1..11.

Example

Some solutions for n=6:
.-7...-6...-7...-7...-5...-7...-5...-5...-5...-7...-6...-7...-6...-5...-6...-4
..1....1...-3...-1...-5...-4....0...-3...-3...-1....0...-1...-5...-2....1...-2
..7....4....4...-4....5....4....2....0...-1....5....3...-3...-2...-1....1...-1
.-7....3....0....4...-1....6...-4....0....2...-5...-5....3....1....6...-5...-4
..2...-5....5....1....1....0....1....7....2....7....5....4....7...-2....6....7
..4....3....1....7....5....1....6....1....5....1....3....4....5....4....3....4

Crossrefs

Sequence in context: A296830 A232621 A303176 * A209343 A270523 A332916

Adjacent sequences: A209481 A209482 A209483 * A209485 A209486 A209487

Keyword

nonn

Author

R. H. Hardin, Mar 09 2012

Status

approved