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On Repdigits Which are Sums or Differences of Two k-Pell Numbers

  • Mariama Ndao Faye , Salah Eddine Rihane and Alain Togbé EMAIL logo
Published/Copyright: December 18, 2023
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ABSTRACT

Let k ≥ 2. A generalization of the well-known Pell sequence is the k-Pell sequence whose first k terms are 0,…, 0, 1 and each term afterwards is given by the linear recurrence

pn(k)=2Pn1(k)+Pn2(k)++Pnk(k).

The goal of this paper is to show that 11, 33, 55, 88 and 99 are all repdigits expressible as sum or difference of two k-Pell. The proof of our main theorem uses lower bounds for linear forms in logarithms of algebraic numbers and a modified version of Baker-Davenport reduction method (due to Dujella and Pethő). This extends a result of Bravo and Herrera [Repdigits in generalized Pell sequences, Arch. Math. (Brno) 56(4) (2020), 249–262].

2020 Mathematics Subject Classification: Primary 11B39; 11J86

(Communicated by István Gaál)


Acknowledgement

The authors would like to express their gratitude to the reviewer for the careful reading of this paper and the remarks which have qualitatively improved the work. The third author is partially supported by Purdue University Northwest.

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Received: 2022-06-12
Accepted: 2023-02-28
Published Online: 2023-12-18

© 2023 Mathematical Institute Slovak Academy of Sciences

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