Question 171
For each positive integer $n$ let $d(n)$ be the number of prime divisors of $n$. Show that for each positive integer $n$ there are positive integers $k, m$ satisfying $k - m = n$ and $d(k) - d(m) = 1$.
Math Olympiad Vault · MathNet 2017-part-06 — 176 problems (EN–VI)