The denominator part is easy its equation is (4^n)/4, where n is day n

The

**numerator** part is the part I cannot figure out.

Going from 5 to 9, --- I add 4 ---- Day 2 = Day 1 + 4^(n-1)

Going from 9 to 25, --- I add 4^2 --- Day 3 = Day 2 + 4^(n-1)

Going from 25 to 89 --- I add 4^3 --- Day 4 = Day 3 + 4^(n-1)

So Going from day 5 to day 6 I need to add 4^5

But what If I want to know day 10 without knowing the previous day?

Is It Possible?

I'm sorry that I did not properly explain the problem, again I thank you for taking the time to respond