A208985 Number of n-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and first differences in -n..n.

1, 2, 5, 33, 351, 5404, 104001, 2416967, 65820325, 2058166065, 72731671225

Offset

1,2

Comments

Diagonal of A208993.

Links

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

Example

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

Crossrefs

Sequence in context: A198089 A366327 A197974 * A333738 A114793 A254429

Adjacent sequences: A208982 A208983 A208984 * A208986 A208987 A208988

Keyword

nonn

Author

R. H. Hardin, Mar 04 2012

Status

approved