Question 74
Let $\delta(n)$ denote the number of positive divisors of positive integer $n$. Prove that there exist infinitely many positive integers that can not be represented in the form
$$
\left( \frac{2\sqrt{n}}{\delta(n)} \right)^2
$$
for positive integers $n$.
$$
\left( \frac{2\sqrt{n}}{\delta(n)} \right)^2
$$
for positive integers $n$.