Smooth numbers in Beatty sequences
Volume 200 / 2021
Abstract
Let be an irrational number of finite type and let \psi \ge 0. We consider numbers in the Beatty sequence of integer parts, \mathcal B(x) = \{\lfloor \theta n + \psi \rfloor : 1 \le n \le x\}. Let C \gt 3. Writing P(n) for the largest prime factor of n and |\ldots | for cardinality, we show that |\{n\in \mathcal B(x) : P(n) \le y\}| = \frac 1\theta \, \Psi (\theta x, y) (1 + o(1)) as x\to \infty , uniformly for y \ge (\log x)^C. Here \Psi (X,y) denotes the number of integers up to X with P(n) \le y. The range of y extends that given by Akbal (2020). The work of Harper (2016) plays a key role in the proof.