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A208940
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Number of n-bead necklaces labeled with numbers -3..3 not allowing reversal, with sum zero with no three beads in a row equal.
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0
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1, 4, 12, 57, 274, 1464, 7974, 45050, 260046, 1529746, 9129838, 55159410, 336661016, 2072786142, 12858170994, 80288297320, 504231724034
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listen;
history;
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internal format)
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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Some solutions for n=5:
.-2...-3...-3...-3...-3...-2...-3...-2...-2...-3...-3...-2...-3...-3...-2...-2
..1...-2....2....0....3....2....1....1...-2...-3....3...-2...-1...-1....0...-1
.-1....3....1....0...-2...-2....1....1....0....3...-3....2....3....3...-1....2
.-1....3...-1....3....2....3....2...-2....2....0....3....3....3...-2....2...-2
..3...-1....1....0....0...-1...-1....2....2....3....0...-1...-2....3....1....3
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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