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 A209337 Number of n-bead necklaces labeled with numbers -1..1 allowing reversal, with sum zero with no three beads in a row equal. 0
 1, 2, 1, 4, 5, 14, 21, 51, 102, 249, 555, 1358, 3201, 7890, 19232, 47869, 118955, 298875, 752039, 1904621, 4835666, 12330144, 31521037, 80836979, 207803455, 535535393, 1383064966, 3579351724, 9280561947 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 1 of A209344. LINKS EXAMPLE Some solutions for n=10: .-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1...-1 ..0....0...-1....0...-1....0....0....0....0...-1....0....0....0....0....0....0 .-1....0....0....0....0....0....0...-1...-1....0...-1....0....0...-1....1...-1 ..0...-1....0....1...-1...-1...-1....0....0...-1....1...-1....1....1....0....0 ..0....0...-1....0....1....0....1....1....1....1....1....0...-1...-1...-1....0 ..1....1....0...-1....0....0...-1...-1...-1....1...-1....1....1....1....1....1 ..1....0....1....1....1....1....1....1....1...-1....0...-1....0....0...-1....0 ..0....1....0...-1....0....0....0....0...-1....1...-1....0....0....1....1....1 .-1...-1....1....1....1....0....0....0....1....0....1....1...-1...-1...-1....0 ..1....1....1....0....0....1....1....1....1....1....1....1....1....1....1....0 CROSSREFS Sequence in context: A350087 A091232 A336398 * A243004 A137424 A083007 Adjacent sequences:  A209334 A209335 A209336 * A209338 A209339 A209340 KEYWORD nonn AUTHOR R. H. Hardin, Mar 06 2012 STATUS approved

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Last modified August 13 20:49 EDT 2022. Contains 356107 sequences. (Running on oeis4.)