[![enter image description here](https://i.stack.imgur.com/9AVQh.png)](https://i.stack.imgur.com/9AVQh.png)

My questions:

1. For the inner summation, When $j=i$ does that mean $j$ will equal $2$ because $i$ equals $2$?
2. I'm confused and stuck on the yellow, because I thought it would just be $n$. NOT ($(n-i+n)$. I understandstand Line 1 of the problem somewhat. It's just the index of the inner j=i is throwing me off.