A208944 Number of n-bead necklaces labeled with numbers -7..7 not allowing reversal, with sum zero with no three beads in a row equal.

1, 8, 56, 563, 6004, 68722, 817362, 10024344, 125779236, 1607175818, 20840635620, 273560222248

Offset

1,2

Comments

Column 7 of A208945.

Links

Table of n, a(n) for n=1..12.

Example

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

Crossrefs

Cf. A208945.

Sequence in context: A098914 A009107 A209665 * A209072 A133671 A326239

Adjacent sequences: A208941 A208942 A208943 * A208945 A208946 A208947

Keyword

nonn

Author

R. H. Hardin, Mar 03 2012

Status

approved