Question 16
Let $a \geq 4$ be a positive integer. Determine the smallest value of $n \geq 5$, such that $a$ can be represented in the form
$$
\sigma = \frac{x_1^2 + x_2^2 + \dots + x_n^2}{x_1 x_2 \dots x_n}
$$
for a proper choice of positive integers $n$ $x_1, x_2, \dots, x_n$.
$$
\sigma = \frac{x_1^2 + x_2^2 + \dots + x_n^2}{x_1 x_2 \dots x_n}
$$
for a proper choice of positive integers $n$ $x_1, x_2, \dots, x_n$.