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A208939
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Number of n-bead necklaces labeled with numbers -2..2 not allowing reversal, with sum zero with no three beads in a row equal.
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0
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1, 3, 6, 22, 68, 264, 988, 3954, 15980, 66146, 277190, 1177152, 5047672, 21838420, 95184446, 417606390, 1842715198, 8172736366, 36412668752, 162897497434, 731442664136
(list;
graph;
refs;
listen;
history;
text;
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...-2...-2...-2...-1...-2...-2...-2...-2...-2...-2...-2...-2...-1...-1...-1
.-1...-2....1....2....0....0....1....0...-1....2....0....1...-1...-1...-1....0
.-1....2....0....1....0....2....1....1....0....1....0....2....0....2....1...-1
..2....1....0....0...-1...-2...-2...-1....1...-1....1...-1....2...-1....0....0
..2....1....1...-1....2....2....2....2....2....0....1....0....1....1....1....2
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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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