MathNet 2010 — Part 05 Question 158

Let $f: \mathbb{N} \rightarrow \mathbb{N}$ be a strictly increasing function such that $f(f(n))=3 n$, for all $n \in \mathbb{N}$. Find $f(2010)$.
(Note: $\mathbb{N}=\{0,1,2, \ldots\}$ ).