A lower bound on the LCM of polynomial sequences

Abstract

Let $f$ be a polynomial $f$ of degree $d\ge 2$ with integer coefficients which is irreducible over the rationals. Cilleruelo conjectured that the least common multiple of the values of the polynomial at the first $N$ integers satisfies $\log lcm(f(1),\dots, f(N)) \sim (d-1) N\log N$ as $N\to \infty$. This is only known for degree $d=2$. In this note we give a simple lower bound for all degrees $d\geq 2$ which is consistent with the conjecture: $\log lcm (f(1),\dots, f(N)) \gg N\log N$.