Exercise 1.19. Using the summation formulas n n n(n + 1) n(n + 1)(2n+1) 2 = 2 6 i=1 i=1 find the flop count for the following sequence of commands: a = 0; for p = 1:n for q = p: n for rq:n a = a+1; end end end What will be the value of a after the commands are executed?