What comes next: 2, 6, 5, 14, 11, 26, 17, ?

Answer 1

2 + (4) = 6 : 6 - 3^0 = 5
5 + (4 + 5) = 14 : 14 - 3^1 = 11
11 + (4 + 5 + 6) = 26 : 26 - 3^2 = 17.
17 + (4 + 5 + 6 + 7) = 39.