English

A Fibonacci type sequence with Prouhet-Thue-Morse coefficients

Number Theory 2021-10-01 v1 Formal Languages and Automata Theory

Abstract

Let tn=(1)s2(n)t_n = (-1)^{s_2(n)}, where s2(n)s_2(n) is the sum of binary digits function. The sequence (tn)nN(t_n)_{n\in \mathbb N} is the well-known Prouhet-Thue-Morse sequence. In this note we initiate the study of the sequence (hn)nN(h_n)_{n\in \mathbb N}, where h0=0,h1=h_0 = 0, h_1 = 1 and for n2n \ge 2 we define hnh_n recursively as follows:hn=tnhn1+hn2 h_n = t_n h_{n-1} + h_{n-2}. We prove several results concerning arithmetic properties of the sequence (hn)nN(h_n )_{n\in \mathbb N}. In particular, we prove non-vanishing of hnh_n for n5n \ge 5, automaticity of the sequence (hn(modm))nN(h_n \pmod m)_{n\in \mathbb N} for each m, and other results.

Keywords

Cite

@article{arxiv.2109.15243,
  title  = {A Fibonacci type sequence with Prouhet-Thue-Morse coefficients},
  author = {Eryk Lipka and Maciej Ulas},
  journal= {arXiv preprint arXiv:2109.15243},
  year   = {2021}
}

Comments

32 pages, 10 figures

R2 v1 2026-06-24T06:31:47.918Z