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 A209478 Number of n-bead necklaces labeled with numbers -1..1 allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2. 0
 1, 2, 1, 4, 4, 11, 15, 43, 77, 199, 423, 1080, 2514, 6355, 15529, 39429, 98875, 252551, 643133, 1653677, 4254070, 11005241, 28518931, 74179434, 193328017, 505236093, 1322919905, 3471492272, 9125743338 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 1 of A209485. LINKS EXAMPLE Some solutions for n=10: .-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1 .-1....0...-1...-1...-1....0...-1...-1....0....0....0....0...-1...-1...-1...-1 ..1....0....0....0....1....0....1....1...-1...-1...-1....0...-1....0....0....0 .-1...-1....0....0...-1...-1...-1...-1....1....1....1....1....1....0....0....0 ..0....0....0....1....1....0....0....0...-1...-1....0...-1...-1....1....0....0 ..0....0....0....1...-1....0....0....0....0....1....0....0....1....0....0....0 ..0....0....0...-1....1....1...-1....0....0...-1...-1....0....1....0....1....1 ..0....0....1...-1...-1....0....1....1....1....1....1....1....0...-1...-1....1 ..1....1....0....1....1....0....1....0....0....0....0....0....0....1....1....0 ..1....1....1....1....1....1....1....1....1....1....1....0....1....1....1....0 CROSSREFS Sequence in context: A241513 A095293 A034409 * A211178 A048049 A212716 Adjacent sequences:  A209475 A209476 A209477 * A209479 A209480 A209481 KEYWORD nonn AUTHOR R. H. Hardin, Mar 09 2012 STATUS approved

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Last modified August 9 01:35 EDT 2020. Contains 336310 sequences. (Running on oeis4.)