Functional analysis

Let $f(n)$ be a function defined on the non-negative integer $n$ such that $f(0)=f(1)=0$ , $f(2)=1$ and for $n>2$ , $f(n)$ gives the smallest positive integer which does not divide $n$ . Find

$\large \sum_{k=1}^{2017}f(f(f(k)))$