I don't even qualify as a novice, but it seems f(the first iteration) would need start with 0. With this sequence of numbers 1,1,2,3,5,8 it seems to be calcula

I don't even qualify as a novice, but it seems f(the first iteration) would need start with 0. With this sequence of numbers 1,1,2,3,5,8 it seems to be calculating f=0 as 2 * 0+1=1 ; f=1 as 2 * 1+1=3 ; f=2 as 2 * 2+1=5 ; f=3 as 2 * 3+2=8 ; then f=4 should be 2*5+3=13 I'm not sure how 2 is calculated unless i=0, but this is why I'm not even a novice.