A208824 Number of n-bead necklaces labeled with numbers -7..7 allowing reversal, with sum zero.

1, 8, 32, 316, 3085, 35288, 417204, 5134796, 64630243, 829140440, 10794728782, 142275197892, 1894548608563

Offset

1,2

Comments

Column 7 of A208825.

Links

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

Example

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

Crossrefs

Sequence in context: A066415 A143557 A348399 * A034193 A159277 A214539

Adjacent sequences: A208821 A208822 A208823 * A208825 A208826 A208827

Keyword

nonn

Author

R. H. Hardin, Mar 01 2012

Status

approved