Question 118
Find all functions $f: \mathbb{N}^* \rightarrow \mathbb{N}^*$ such that
$$
f^{f(n)}(m) + m n = f(m) f(n)
$$
for all $m, n \in \mathbb{N}^*$.
$$
f^{f(n)}(m) + m n = f(m) f(n)
$$
for all $m, n \in \mathbb{N}^*$.
MathNet 2023-part-02 — 191 problems (EN–VI) Question 118
Math Olympiad Vault · MathNet 2023-part-02 — 191 problems (EN–VI)