2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/136159We study the primitive divisors of the terms of $(Δ_n)_{n \geq 1}$, where $Δ_n=N_{K/ \mathbb{Q}}(u^n-1)$ for $K$ a real quadratic field, and $u>1$ a unit element of its ring of integers. The methods used allow us to find the terms of the sequence that do not have a primitive prime divisor.10 pagesNumber Theory11A51, 11B37text