Question:
Determine the subgroup lattice for $\mathbb{Z}_{p^2 q}$ where $p, q$ are distinct primes.
Indeed, $\left | \mathbb{Z}_{p^2 q} \right | = p^2 q$
The unique subgroups of $\mathbb{Z}_{p^2 q}$ are of the form $\left \langle \frac{p^2 q}{k} \right \rangle$ for each positive divisor $k$ of $n$.
My knowledge of primes are lacking. Any hint(s) would be helpful. Maybe $k$ divides $p^2 q$ implies $k$ divides $p^2$ or $k$ divides $q$ might be helpful?
Thanks in advance.