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 A209075 Number of 6-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and avoiding the pattern z z+1 z+2. 1
 19, 265, 1465, 5239, 14431, 33469, 68723, 128845, 225127, 371859, 586669, 890881, 1309873, 1873417, 2616037, 3577367, 4802491, 6342301, 8253855, 10600717, 13453315, 16889299, 20993881, 25860193, 31589645, 38292265, 46087057, 55102359 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 6 of A209073. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 5*a(n-1) - 10*a(n-2) + 11*a(n-3) - 10*a(n-4) + 11*a(n-5) - 10*a(n-6) + 5*a(n-7) - a(n-8) for n > 9. Empirical g.f.: x*(19 + 170*x + 330*x^2 + 355*x^3 + 161*x^4 + 30*x^5 - 16*x^6 + 9*x^7 - 2*x^8) / ((1 - x)^6*(1 + x + x^2)). - Colin Barker, Jul 08 2018 EXAMPLE Some solutions for n=6: -4 -5 -4 -5 -5 -5 -4 -3 -5 -5 -5 -5 -5 -6 -6 -5 3 -2 4 -1 -1 -3 3 2 1 5 -1 -1 -5 6 2 5 1 5 3 -2 4 -1 -3 -2 0 0 4 4 5 2 4 0 1 -4 -1 6 -2 3 3 -1 4 -4 -2 -4 6 -4 1 -2 -3 4 -2 4 -2 2 -2 1 0 5 -1 6 -5 6 3 -4 2 2 0 -2 6 4 3 3 0 -1 5 0 4 -4 -4 6 CROSSREFS Cf. A209073. Sequence in context: A294828 A016257 A021104 * A017161 A036736 A016254 Adjacent sequences: A209072 A209073 A209074 * A209076 A209077 A209078 KEYWORD nonn AUTHOR R. H. Hardin, Mar 04 2012 STATUS approved

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Last modified September 23 16:46 EDT 2023. Contains 365554 sequences. (Running on oeis4.)