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A208819
Number of n-bead necklaces labeled with numbers -2..2 allowing reversal, with sum zero.
0
1, 3, 5, 16, 45, 167, 609, 2471, 10143, 43223, 186533, 818836, 3629835, 16250859, 73300289, 332895316, 1520604469, 6981991345, 32205476541
OFFSET
1,2
COMMENTS
Column 2 of A208825.
EXAMPLE
All solutions for n=3:
.-2...-1...-1...-2....0
..1....0...-1....0....0
..1....1....2....2....0
CROSSREFS
Sequence in context: A371868 A243321 A099101 * A038120 A192911 A105408
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 01 2012
STATUS
approved