A note on univoque self-sturmian numbers

Jean-Paul Allouche

Displaying similar documents to “A note on univoque self-sturmian numbers”

Imbalances in Arnoux-Rauzy sequences

Julien Cassaigne, Sébastien Ferenczi, Luca Q. Zamboni (2000)

Annales de l'institut Fourier

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In a 1982 paper Rauzy showed that the subshift $(X, T)$ generated by the morphism $1 \mapsto 12$ , $2 \mapsto 13$ and $3 \mapsto 1$ is a natural coding of a rotation on the two-dimensional torus $𝕋^{2}$ , i.e., is measure-theoretically conjugate to an exchange of three fractal domains on a compact set in $ℝ^{2},$ each domain being translated by the same vector modulo a lattice. It was believed more generally that each sequence of block complexity $2 n + 1$ satisfying a combinatorial criterion known as the $☆$ condition of Arnoux and Rauzy codes the orbit...

On some properties of doubly-periodic words

Claudio Baiocchi (1997)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

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We study the functional equation: $(1) A B C = C D A$ where $A, B, C$ and $D$ are words over an alphabet $A$ . In particular we prove a «structure result» for the inner factors $B, D$ : for suitably chosen words $X, Y, Z$ one has: $(2) B = X Y Z$ , $D = Z Y X$ $(2) B = X Y Z$ , $D = Z Y X$ $(2) B = X Y Z$ , $D = Z Y X$ $(2) B = X Y Z$ , $D = Z Y X$ . It is a generalization of the Lyndon-Schützenberger's Theorem (see [7]): if in (1) $A$ or $C$ is empty, formula (2) holds true with one among $X, Y, Z$ which can be chosen empty.

Binary equality words with two $b$ ’s

Štěpán Holub, Jiří Sýkora (2018)

Commentationes Mathematicae Universitatis Carolinae

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Deciding whether a given word is an equality word of two nonperiodic morphisms is also known as the dual Post correspondence problem. Although the problem is decidable, there is no practical decision algorithm. Already in the binary case, the classification is a large project dating back to 1980s. In this paper we give a full classification of binary equality words in which one of the letters has two occurrences.

On the intersection of two distinct $k$ -generalized Fibonacci sequences

Diego Marques (2012)

Mathematica Bohemica

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Let $k \geq 2$ and define $F^{(k)} : = {(F_{n}^{(k)})}_{n \geq 0}$ , the $k$ -generalized Fibonacci sequence whose terms satisfy the recurrence relation $F_{n}^{(k)} = F_{n - 1}^{(k)} + F_{n - 2}^{(k)} + \dots + F_{n - k}^{(k)}$ , with initial conditions $0, 0, \dots, 0, 1$ ( $k$ terms) and such that the first nonzero term is $F_{1}^{(k)} = 1$ . The sequences $F : = F^{(2)}$ and $T : = F^{(3)}$ are the known Fibonacci and Tribonacci sequences, respectively. In 2005, Noe and Post made a conjecture related to the possible solutions of the Diophantine equation $F_{n}^{(k)} = F_{m}^{(ℓ)}$ . In this note, we use transcendental tools to provide a general method for finding the intersections $F^{(k)} \cap F^{(m)}$ which gives...

Piatetski-Shapiro sequences via Beatty sequences

Lukas Spiegelhofer (2014)

Acta Arithmetica

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Integer sequences of the form $⌊ n^{c} ⌋$ , where 1 < c < 2, can be locally approximated by sequences of the form ⌊nα+β⌋ in a very good way. Following this approach, we are led to an estimate of the difference $\sum_{n \leq x} φ (⌊ n^{c} ⌋) - 1 / c \sum_{n \leq x^{c}} φ (n) n^{1 / c - 1}$ , which measures the deviation of the mean value of φ on the subsequence $⌊ n^{c} ⌋$ from the expected value, by an expression involving exponential sums. As an application we prove that for 1 < c ≤ 1.42 the subsequence of the Thue-Morse sequence indexed by $⌊ n^{c} ⌋$ attains both of its values with...

On the distance between generalized Fibonacci numbers

Jhon J. Bravo, Carlos A. Gómez, Florian Luca (2015)

Colloquium Mathematicae

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For an integer k ≥ 2, let $(F ₙ^{(k)}) ₙ$ be the k-Fibonacci sequence which starts with 0,..., 0,1 (k terms) and each term afterwards is the sum of the k preceding terms. This paper completes a previous work of Marques (2014) which investigated the spacing between terms of distinct k-Fibonacci sequences.

Average Value of the Euler Function on Binary Palindromes

William D. Banks, Igor E. Shparlinski (2006)

Bulletin of the Polish Academy of Sciences. Mathematics

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We study values of the Euler function φ(n) taken on binary palindromes of even length. In particular, if $ℬ_{2 ℓ}$ denotes the set of binary palindromes with precisely 2ℓ binary digits, we derive an asymptotic formula for the average value of the Euler function on $ℬ_{2 ℓ}$ .

Expansions of binary recurrences in the additive base formed by the number of divisors of the factorial

Florian Luca, Augustine O. Munagi (2014)

Colloquium Mathematicae

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We note that every positive integer N has a representation as a sum of distinct members of the sequence ${d (n!)}_{n \geq 1}$ , where d(m) is the number of divisors of m. When N is a member of a binary recurrence $u = {u ₙ}_{n \geq 1}$ satisfying some mild technical conditions, we show that the number of such summands tends to infinity with n at a rate of at least c₁logn/loglogn for some positive constant c₁. We also compute all the Fibonacci numbers of the form d(m!) and d(m₁!) + d(m₂)! for some positive integers m,m₁,m₂. ...

On square classes in generalized Fibonacci sequences

Zafer Şiar, Refik Keskin (2016)

Acta Arithmetica

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Let P and Q be nonzero integers. The generalized Fibonacci and Lucas sequences are defined respectively as follows: U₀ = 0, U₁ = 1, V₀ = 2, V₁ = P and $U_{n + 1} = P U ₙ + Q U_{n - 1}$ , $V_{n + 1} = P V ₙ + Q V_{n - 1}$ for n ≥ 1. In this paper, when w ∈ 1,2,3,6, for all odd relatively prime values of P and Q such that P ≥ 1 and P² + 4Q > 0, we determine all n and m satisfying the equation Uₙ = wUₘx². In particular, when k|P and k > 1, we solve the equations Uₙ = kx² and Uₙ = 2kx². As a result, we determine all n such that Uₙ = 6x². ...

On the golden number and Fibonacci type sequences

Eugeniusz Barcz (2019)

Annales Universitatis Paedagogicae Cracoviensis | Studia ad Didacticam Mathematicae Pertinentia

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The paper presents, among others, the golden number $ϕ$ as the limit of the quotient of neighboring terms of the Fibonacci and Fibonacci type sequence by means of a fixed point of a mapping of a certain interval with the help of Edelstein’s theorem. To demonstrate the equality , where $f_{n}$ is $n$ -th Fibonacci number also the formula from Corollary has been applied. It was obtained using some relationships between Fibonacci and Lucas numbers, which were previously justified.