Logic formulas

Hi,

(Please see attachment).
The first bordered area is the formula pattern I typed in manually to produce the second bordered area below.
I want to come up with a formula that could be pasted into an area of any size (say 10 rows deep (not including the first row)) that would effectively produce what the manual entry of formulas does. The pattern is easy to see, but is proving difficult to implement using only worksheet formulas.

Each formula must reference the column to the left, but based on the particular number in the cycle (the first row) the pattern forms..

I have tried using function such as offset etc but haven't so far come up with the solution.

Any pointers

Thanks in advance