English

Repdigits in k-generalized Pell sequence

Number Theory 2020-09-29 v1

Abstract

Let k2k\geq 2 and let (Pn(k))n2k(P_{n}^{(k)})_{n\geq 2-k} be kk-generalized Pell sequence defined by \begin{equation*}P_{n}^{(k)}=2P_{n-1}^{(k)}+P_{n-2}^{(k)}+...+P_{n-k}^{(k)}\end{equation*} for n2n\geq 2 with initial conditions \begin{equation*}P_{-(k-2)}^{(k)}=P_{-(k-3)}^{(k)}=\cdot \cdot \cdot =P_{-1}^{(k)}=P_{0}^{(k)}=0,P_{1}^{(k)}=1. \end{equation*} In this paper, we deal with the Diophantine equation \begin{equation*}P_{n}^{(k)}=d\left( \frac{10^{m}-1}{9}\right)\end{equation*} in positive integers n,m,k,dn,m,k,d with k2,k\geq 2, m2m\geq 2 and 1d91\leq d\leq 9. We will show that repdigits with at least two digits in the sequence (Pn(k))n2k\left( P_{n}^{(k)}\right)_{n\geq 2-k} are the numbers\ P5(3)=33P_{5}^{(3)}=33 and P6(4)=88.P_{6}^{(4)}=88.

Cite

@article{arxiv.2009.13387,
  title  = {Repdigits in k-generalized Pell sequence},
  author = {Zafer Şiar and Refik Keskin},
  journal= {arXiv preprint arXiv:2009.13387},
  year   = {2020}
}
R2 v1 2026-06-23T18:51:01.205Z