English

Coprimality of elements in regular sequences with polynomial growth

Number Theory 2025-06-27 v1

Abstract

The investigation of primes in certain arithmetic sequences is one of the fundamental problems in number theory and especially, finding blocks of distinct primes has gained a lot of attention in recent years. In this context, we prove the existence of long blocks of kk-wise coprime elements in certain regular sequences. More precisely, we prove that for any positive integers Hk2H \geq k \geq 2 and for a real-valued kk-times continuously differentiable function fCk([1,))f \in \mathcal{C}^k\left( [1, \infty)\right) satisfying limxf(k)(x)=0\lim_{x \to \infty} f^{(k)}(x) = 0 and lim supxf(k1)(x)=\limsup_{x \to \infty} f^{(k-1)}(x) = \infty, there exist infinitely many positive integers nn such that gcd(f(n+i1),f(n+i2),,f(n+ik)) = 1 \gcd\left( \lfloor f(n+i_1)\rfloor, \lfloor f(n+i_2)\rfloor, \cdots, \lfloor f(n+i_k)\rfloor \right) ~=~ 1 for any integers 1i1<i2<<ikH1 \leq i_1 < i_2 < \cdots < i_k \leq H. Further, we show that there exists a subset AN\mathcal{A} \subseteq \mathbb{N} having upper Banach density one such that gcd(f(n1),f(n2),,f(nk)) = 1 \gcd\left(\lfloor f(n_1) \rfloor, \lfloor f(n_2) \rfloor, \cdots, \lfloor f(n_k) \rfloor\right) ~=~ 1 for any distinct integers n1,n2,,nkAn_1, n_2, \cdots, n_k \in \mathcal{A}.

Keywords

Cite

@article{arxiv.2506.20956,
  title  = {Coprimality of elements in regular sequences with polynomial growth},
  author = {Jean-Marc Deshouillers and Sunil Naik},
  journal= {arXiv preprint arXiv:2506.20956},
  year   = {2025}
}
R2 v1 2026-07-01T03:33:56.328Z