login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A064353 Kolakoski-(1,3) sequence: a(n) is length of n-th run. 12
1, 3, 3, 3, 1, 1, 1, 3, 3, 3, 1, 3, 1, 3, 3, 3, 1, 1, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 1, 1, 3, 3, 3, 1, 3, 1, 3, 3, 3, 1, 1, 1, 3, 3, 3, 1, 3, 3, 3, 1, 1, 1, 3, 3, 3, 1, 3, 3, 3, 1, 1, 1, 3, 3, 3, 1, 3, 1, 3, 3, 3, 1, 1, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 1, 1, 3, 3, 3, 1, 3, 1, 3, 3, 3, 1, 1, 1, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The frequency of the number '3' is 0.6027847... See UWC link. - Jaap Spies, Dec 12 2004

13, 13331, 13331113331 are primes. - Vincenzo Librandi, Mar 02 2016

REFERENCES

E. Angelini, "Jeux de suites", in Dossier Pour La Science, pp. 32-35, Volume 59 (Jeux math'), April/June 2008, Paris.

LINKS

Reinhard Zumkeller, 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.

UWC, Opgave A (solution)

MATHEMATICA

A = {1, 3, 3, 3}; i = 3; next = 1; While[Length[A] < 140, A = Join[A, next*Array[1&, A[[i]]]]; i++; next = 4-next]; A (* Jean-Fran├žois Alcover, Nov 12 2016, translated from MATLAB *)

PROG

(MATLAB) A = [1 3 3 3]; i = 3; next = 1; while length(A) < 140 A = [A next*ones(1, A(i))]; i = i + 1; next = 4 - next; end

(Haskell) -- from John Tromp's a000002.hs

a064353 n = a064353_list !! (n-1)

a064353_list = 1 : 3 : drop 2

   (concat . zipWith replicate a064353_list . cycle $ [1, 3])

-- Reinhard Zumkeller, Aug 02 2013

CROSSREFS

Cf. A000002, A071820, A071907, A071928, A071942.

Sequence in context: A177693 A131289 A130974 * A190906 A080311 A135368

Adjacent sequences:  A064350 A064351 A064352 * A064354 A064355 A064356

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from David Wasserman, Jul 16 2002

Edited by Charles R Greathouse IV, Apr 20 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified January 21 21:01 EST 2017. Contains 281110 sequences.