A209068 - OEIS

A209068

Number of n-bead necklaces labeled with numbers -3..3 not allowing reversal, with sum zero and avoiding the pattern z z+1 z+2.

1, 4, 12, 57, 276, 1465, 8008, 45408, 263168, 1554582, 9318412, 56549840, 346717662, 2144555617, 13365472929, 83848948043, 529091046781, 3355802952070

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Column 3 of A209073.

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

Some solutions for n=6:

.-2...-2...-2...-3...-2...-2...-3...-3...-2...-2...-3...-2...-2...-3...-3...-3

..0...-1....1....2....2....2....3...-1...-2....2....1....3...-1...-3....1....3

..1....3....2....1...-1....0....1....0....3....0....3....1....1....3....1....2

.-1....0...-1...-2....3....1....3....3...-1...-2...-1...-1....2....2....0....0

..3...-1....0....3...-1....0...-2...-1....0....3....1....0....1....3...-1...-1

.-1....1....0...-1...-1...-1...-2....2....2...-1...-1...-1...-1...-2....2...-1

CROSSREFS

Cf. A209073.

Sequence in context: A197924 A065125 A208940 * A177265 A243923 A192331

Adjacent sequences: A209065 A209066 A209067 * A209069 A209070 A209071

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 04 2012

STATUS

approved