A208937 Number of n-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero with no three beads in a row equal.

1, 3, 12, 122, 1722, 33468, 817362, 24184890, 841286276, 33675904820, 1525641905390

Offset

1,2

Comments

Diagonal of A208945.

Links

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

Example

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

Crossrefs

Sequence in context: A010571 A280248 A067124 * A209065 A124153 A162127

Adjacent sequences: A208934 A208935 A208936 * A208938 A208939 A208940

Keyword

nonn

Author

R. H. Hardin, Mar 03 2012

Status

approved