Problems(1)
Determine all positive integers expressible, for every integer n \geq 3 , in the form
\begin{align*}
\frac{(a_1 + 1)(a_2 + 1) \ldots (a_n + 1) - 1}{a_1a_2 \ldots a_n},
\end{align*}
where a1,a2,…,an are pairwise distinct positive integers. roDiophantine Equations