Question 154
Find all functions $f: \mathbb{Z} \rightarrow \mathbb{Z}$ satisfying
$$
f(m+n)+f(m n-1)=f(m) f(n)+2
$$
for all $m, n \in \mathbb{Z}$.
$$
f(m+n)+f(m n-1)=f(m) f(n)+2
$$
for all $m, n \in \mathbb{Z}$.
MathNet 2009-part-02 — 175 problems (EN–VI) Question 154
Math Olympiad Vault · MathNet 2009-part-02 — 175 problems (EN–VI)