A208969 Number of n-bead necklaces labeled with numbers -7..7 allowing reversal, with sum zero and first and second differences in -7..7.

1, 2, 5, 24, 130, 967, 7425, 58791, 458768, 3587596, 28252771, 224912985, 1809574254

Offset

1,2

Comments

Column 7 of A208970.

Links

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

Example

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

Crossrefs

Sequence in context: A346204 A330512 A194349 * A020022 A026073 A054131

Adjacent sequences: A208966 A208967 A208968 * A208970 A208971 A208972

Keyword

nonn

Author

R. H. Hardin, Mar 03 2012

Status

approved