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 A208999 Number of n-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and first and second differences in -n..n. 0
 1, 1, 3, 10, 71, 923, 14701, 279721, 6025413, 146448941, 3999932289 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Diagonal of A209007. LINKS EXAMPLE Some solutions for n=6: .-3...-5...-2...-2...-5...-2...-4...-5...-2...-2...-3...-4...-2...-4...-3...-5 .-1...-2...-1...-2...-5...-2...-4...-3...-2...-2...-1....0....0...-4....0...-4 ..0....4...-1....2....1....3...-1....3....1...-1....1....4...-2....2....1....2 ..4....4....2....2....5....2....3....4....3....0....1....4....1....5....3....4 ..2....2....0...-1....3...-1....4....2....1....2....1...-1....2....2...-1....4 .-2...-3....2....1....1....0....2...-1...-1....3....1...-3....1...-1....0...-1 CROSSREFS Sequence in context: A002499 A047833 A047834 * A181075 A136507 A086846 Adjacent sequences:  A208996 A208997 A208998 * A209000 A209001 A209002 KEYWORD nonn AUTHOR R. H. Hardin, Mar 04 2012 STATUS approved

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