Answer:

152, 207

The n^th number in the sequence is n multiplied by the n^th prime.

1 x 2 = 2
2 x 3 = 6
3 x 5 = 15
4 x 7 = 28
5 x 11 = 55
6 x 13 = 78
7 x 17 = 119
8 x 19 = 152
9 x 23 = 207

If you have access to the Internet, you can often find the pattern in an integer sequence by looking it up on the OEIS.  This particular sequence is called n*(n-th prime), sequence number A033286.