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 A215331 Smooth necklaces with 5 colors. 1
 1, 5, 9, 16, 35, 76, 190, 455, 1156, 2911, 7438, 18992, 48902, 125968, 325975, 845202, 2197690, 5725854 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS We call a necklace (x[1],x[2],...,x[n]) smooth if abs(x[k]-x[k-1]) <= 1 for 2<=k<=n. LINKS EXAMPLE The smooth pre-necklaces, necklaces (N), and Lyndon words (L) of length 4 with 4 colors (using symbols ".", "1", "2", "3", and "4") are:     ....   1       .  N     ...1   4    ...1  N L     ..1.   3     .1.     ..11   4    ..11  N L     ..12   4    ..12  N L     .1.1   2      .1  N     .11.   3     11.     .111   4    .111  N L     .112   4    .112  N L     .121   4    .121  N L     .122   4    .122  N L     .123   4    .123  N L     1111   1       1  N     1112   4    1112  N L     1121   3     121     1122   4    1122  N L     1123   4    1123  N L     1212   2      12  N     1221   3     221     1222   4    1222  N L     1223   4    1223  N L     1232   4    1232  N L     1233   4    1233  N L     1234   4    1234  N L     2222   1       2  N     2223   4    2223  N L     2232   3     232     2233   4    2233  N L     2234   4    2234  N L     2323   2      23  N     2332   3     332     2333   4    2333  N L     2334   4    2334  N L     2343   4    2343  N L     2344   4    2344  N L     3333   1       3  N     3334   4    3334  N L     3343   3     343     3344   4    3344  N L     3434   2      34  N     3443   3     443     3444   4    3444  N L     4444   1       4  N There are 43 pre-necklaces, 35 necklaces, and 26 Lyndon words. So a(4) = 35. CROSSREFS Cf. A215327 (smooth necklaces, 3 colors) A215328 (smooth Lyndon words, 3 colors). Sequence in context: A218611 A208669 A062777 * A208725 A272742 A273534 Adjacent sequences:  A215328 A215329 A215330 * A215332 A215333 A215334 KEYWORD nonn,more AUTHOR Joerg Arndt, Aug 08 2012 STATUS approved

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Last modified December 9 19:34 EST 2018. Contains 318023 sequences. (Running on oeis4.)