$p$-adic asymptotic properties of constant-recursive sequences

Abstract

In this article we study $p$-adic properties of sequences of integers (or $p$-adic integers) that satisfy a linear recurrence with constant coefficients. For such a sequence, we give an explicit approximate twisted interpolation to $\mathbb Z_p$. We then use this interpolation for two applications. The first is that certain subsequences of constant-recursive sequences converge $p$-adically. The second is that the density of the residues modulo $p^\alpha$ attained by a constant-recursive sequence converges, as $\alpha \to \infty$, to the Haar measure of a certain subset of $\mathbb Z_p$. To illustrate these results, we determine some particular limits for the Fibonacci sequence.