I would guess 18.
The sequence goes [start], +4, +1, +3, +18, -4, -1 ...
So my guess is that the "minus" part of the sequence follows that of the adding, and the next will be -3. There could be a more complicated solution, but this is what stands out to me.
16 21 22 29
Assuming that you want the numbers that contain the letter 'o' the answer is 22.
22
Eighteen(18)
35
16 21 22 29
22
21
Assuming that you want the numbers that contain the letter 'o' the answer is 22.
31
13 18 16 21 19 24 22 27 25 ... . This series consists of adding 5 to the first number and subtracting 2 from the next number, repeating the sequence in that order.
20
22
22
22
Eighteen(18)
14