The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A332866 Length of shortest ternary squarefree word having n periods. 1
 1, 3, 7, 23, 59 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A word is squarefree if it has no contiguous block inside it of the form xx, for a word x. A period of a word w is an integer 1 <= p <= |w| such that w[i]=w[i+p] for all indices i that make sense.   For example, "alfalfa" has period 3.   Every nonempty word trivially has a period equal to its length. LINKS Daniel Gabric, Narad Rampersad, and Jeffrey Shallit, An inequality for the number of periods in a word, arXiv:2005.11718 [cs.DM], 2020. EXAMPLE Here is a brief table of the lexicographically least words of each length: n=1:  0 n=2: 010 n=3: 0102010 n=4: 01021201021012010212010 n=5: 01021201020121020102120102012021020102120102012102010212010. CROSSREFS Sequence in context: A293466 A231722 A168612 * A127178 A001275 A058757 Adjacent sequences:  A332863 A332864 A332865 * A332867 A332868 A332869 KEYWORD nonn,more AUTHOR Jeffrey Shallit, May 11 2020 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 20 09:40 EDT 2021. Contains 345162 sequences. (Running on oeis4.)