xlarrx$+k\frac{,}{\frac{?}{?}}$larr THIS LINE $($for a$)$

a$.$ Write an expression $($probably involving summations$)$ for how many times the

indicated line of code is executed as a function of $n.$ Simplify the expression

into closed form $($no summation symbols$).$ Show all of your work.

b$.$ What is the big$-$Oh running time of the algorithm, as a function of $n?$