Which is the next number in the sequence: 1, 3, 6, 11, 20, 37, ??

Here the given series is 1, 3, 6, 11, 20, 37, ??,

and the logic behind the series is

1 x 2 + 1 = 3

3 x 2 + 0 = 6

6 x 2 + (-1) = 11

11 x 2 + (-2) = 20

20 x 2 + (-3) = 37

37 x 2 + (-4) = 70

Hence, the next number in the given series is 70.