The set $A$ = {$X_n\mid n\in \Bbb N$} where $X_n = a^{n+1} + a^{n} - 1$, with $a \gt 1, a \in \Bbb Z$.
Show that there are infinitely many numbers that are pairwise coprime.
The set $A$ = {$X_n\mid n\in \Bbb N$} where $X_n = a^{n+1} + a^{n} - 1$, with $a \gt 1, a \in \Bbb Z$.
Show that there are infinitely many numbers that are pairwise coprime.