Problem

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Tags: number theory, relatively prime, Recursive Sequences



Let $x_{1}$ and $x_{2}$ be relatively prime positive integers. For $n \ge 2$, define $x_{n+1}=x_{n}x_{n-1}+1$. Prove that for every $i>1$, there exists $j>i$ such that ${x_{i}}^{i}$ divides ${x_{j}}^{j}$. Is it true that $x_{1}$ must divide ${x_{j}}^{j}$ for some $j>1$?