31 is prime. No tree.
29 is prime. No tree.
43 is prime. No tree.
12
22 2,11
38 2,19
82 2,41
22 2,11
Factor tree for 51: 51 * 1 or 17 * 3 Factor tree for 255: 255 * 1 or 51 * 5
13 is already prime. It doesn't need a tree.
231 77,3 11,7,3
154 77,2 11,7,2