PRIME FACTORS OF $A^n+1$

We find a necessary and sufficient condition that the prime factors of $A^m+1$ and $A^n+1$ coincide for odd positive integers $n>m{\geq}1$. Moreover, we also find a necessary and sufficient condition that the set of all prime factors of $A^m+1$ is a subset of those of $A^n+1$ for $n>m{\geq}1$.