English

On numbers $n$ with polynomial image coprime with the $n$th term of a linear recurrence

Number Theory 2020-12-15 v1

Abstract

Let FF be an integral linear recurrence, GG be an integer-valued polynomial splitting over the rationals, and hh be a positive integer. Also, let AF,G,h\mathcal{A}_{F,G,h} be the set of all natural numbers nn such that gcd(F(n),G(n))=h\gcd(F(n), G(n)) = h. We prove that AF,G,h\mathcal{A}_{F,G,h} has a natural density. Moreover, assuming FF is non-degenerate and GG has no fixed divisors, we show that d(AF,G,1)=0\mathbf{d}(\mathcal{A}_{F,G,1}) = 0 if and only if AF,G,1\mathcal{A}_{F,G,1} is finite.

Keywords

Cite

@article{arxiv.1805.05114,
  title  = {On numbers $n$ with polynomial image coprime with the $n$th term of a linear recurrence},
  author = {Daniele Mastrostefano and Carlo Sanna},
  journal= {arXiv preprint arXiv:1805.05114},
  year   = {2020}
}