2 5 11 8 ? 35 6 13 27
It is 11 which is also a prime number
there is not one
1
71
19,17,15,13,11,9
13 is an unlucky number.
14
The missing number is 26. The number after 29 is 58.
That would be -5.
The spacing is 6 1+6=7 7+6=13 13+6=19 19+6=25 so the missing number in the sequence is 13
11/13
10 (between 7 and 13)