P145. Romania Imar Mathematical Competition
Source:
July 21, 2018
roDiophantine Equations
Problem Statement
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 are pairwise distinct positive integers.