Dio-sequence (Part 1)

A strictly increasing sequence of positive integers $a_1$ , $a_2$ , $a_3$ ,... has the property that for every positive integer $k$ , the subsequence $a_{2k-1}$ , $a_{2k}$ , $a_{2k+1}$ is geometric and the subsequence $a_{2k}$ , $a_{2k+1}$ , $a_{2k+2}$ is arithmetic. If $a_{13}=2016$ , compute $a_1$ .