Answer
33
Work Step by Step
3,6,5,10,9,18,17,34
If have to find the number on the odd position by observing the numbers on the odd position we can see that
3,_,5,_,9,_,17,_,_
3+2 =5
5+(2*2 )=9
9+(2*2*2)=17
17+(2*2*2*2) = 33
therefore the next number is 33