A Problem on Sequence

Define a sequence $u_n$ , where $n = 0,1,2,\ldots$ as follows: $u_0 = 0 , u_1 = 1$ , and for each $n\geq 1$ , $u_{n+1}$ is the smallest positive integer such that $u_{n+1} > u_{n}$ and $\{u_{0}, u_{1},\ldots, u_{n+1} \}$ contains no three elements which are in arithmetic progression. Find $u_{2016}$ .