Question 37
Find all $k \in \mathbb{Z}$ such that there exists a function $f : \mathbb{Z} \to \mathbb{Z}$ satisfying
$$
f(f(n)) = n + k
$$
for all $n \in \mathbb{Z}$.
$$
f(f(n)) = n + k
$$
for all $n \in \mathbb{Z}$.
MathNet 2021 — Part 02 Question 37
Math Olympiad Vault · MathNet 2021 — Part 02