PL-OM 2018 Problem 2

Let $n$ be a positive integer, which gives remainder $4$ of dividing by $8$ . Numbers $1 = k_1 < k_2 < ... < k_m = n$ are all positive diivisors of $n$ . Show that if $i \in \{ 1, 2, ..., m - 1 \}$ isn't divisible by $3$ , then $k_{i + 1} \le 2k_{i}$ .