A209482 Number of n-bead necklaces labeled with numbers -5..5 allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.

1, 6, 17, 128, 866, 7179, 60778, 541494, 4926728, 45758958, 431242307, 4115192739

Offset

1,2

Comments

Column 5 of A209485.

Links

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

Example

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

Crossrefs

Cf. A209485.

Sequence in context: A130278 A024080 A099436 * A209341 A355787 A077022

Adjacent sequences: A209479 A209480 A209481 * A209483 A209484 A209485

Keyword

nonn

Author

R. H. Hardin, Mar 09 2012

Status

approved