I need to know if we can derive any formula to calculate this
$$\sum_{i=k}^n\binom{n}{i}$$
I don't know if this question has been asked or not (or I didn't search for the correct keyword).
While going through the internet, I found that for $i=0$, the sum would be $2^n$. Also, I came across a equation which I think can be used to derive a formula for the above summation, which was $$\binom{n+1}{r}=\binom{n}{r}+\binom{n}{r-1}$$