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A269351 Kolakoski-(1,9) sequence: a(n) is length of n-th run. 2
1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1, 9, 1, 9 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

19, 199, 1999, 199999, 19999999, 1999999999111111111999999999111111111999999999 are primes.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Michael Baake and Bernd Sing, Kolakoski-(3,1) is a (deformed) model set, arXiv:math/0206098 [math.MG], 2002-2003.

MATHEMATICA

seed = {1, 9}; w = {}; i = 1; Do[w = Join[w, Array[seed[[Mod[i - 1, Length[seed]] + 1]]&, If[i > Length[w], seed, w][[i]]]]; i++, {n, 42}]; w

CROSSREFS

Cf. similar sequences listed in A269268.

Sequence in context: A196498 A277535 A292905 * A116667 A259151 A270172

Adjacent sequences:  A269348 A269349 A269350 * A269352 A269353 A269354

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Mar 02 2016

STATUS

approved

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Last modified October 27 22:24 EDT 2021. Contains 348305 sequences. (Running on oeis4.)