English

Cloitre's Self-Generating Sequence

Combinatorics 2025-01-03 v1 Discrete Mathematics Formal Languages and Automata Theory Number Theory

Abstract

In 2009 Benoit Cloitre introduced a certain self-generating sequence (an)n1=1,1,2,1,1,1,1,2,1,1,2,1,1,2,2,,(a_n)_{n\geq 1} = 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, \ldots, with the property that the sum of the terms appearing in the nn'th run equals twice the nn'th term of the sequence. We give a connection between this sequence and the paperfolding sequence, and then prove Cloitre's conjecture about the density of 11's appearing in (an)n1(a_n)_{n \geq 1}.

Keywords

Cite

@article{arxiv.2501.00784,
  title  = {Cloitre's Self-Generating Sequence},
  author = {Jeffrey Shallit},
  journal= {arXiv preprint arXiv:2501.00784},
  year   = {2025}
}