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A209069
Number of n-bead necklaces labeled with numbers -4..4 not allowing reversal, with sum zero and avoiding the pattern z z+1 z+2.
0
1, 5, 20, 122, 766, 5239, 37108, 271732, 2035161, 15526728, 120213839, 942210714, 7461093141, 59602526850, 479745735803
OFFSET
1,2
COMMENTS
Column 4 of A209073.
EXAMPLE
Some solutions for n=6:
.-3...-2...-3...-4...-3...-4...-1...-2...-3...-3...-4...-3...-4...-4...-2...-1
..3...-2....3....3....4...-3...-1....0....2...-1...-2....4...-2...-1...-1...-1
.-1...-2....1...-1...-2....2...-1...-2....3....0....2...-1....3....2...-1....2
.-3....3...-2....4....3....1...-1....0...-2...-1....3....0....3....2....4....0
..4....0....3....1...-2....0....4....1....2....2....3...-2...-4....4...-2....0
..0....3...-2...-3....0....4....0....3...-2....3...-2....2....4...-3....2....0
CROSSREFS
Sequence in context: A054720 A374658 A208941 * A301952 A110373 A081067
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 04 2012
STATUS
approved