What should come in place of the question mark (?) in the given series?
6 4 5 11 39 ?

Logic:  multiply by increasing integers starting from 1, and subtract increasing integers starting from 2.

First term: 6
6 × 1 − 2 = 4
4 × 2 − 3 = 5
5 × 3 − 4 = 11
11 × 4 − 5 = 39
39 × 5 − 6 = 189