6. 8 marks) Consider the sequence ro, x1,... defined by xo = 0, x1 = 1, and xi = x;-1+ i-2 for all i > 2. Consider the following algorithm that attempts to compute the value xn, given an n > 0. Algorithm 6 1: //pre: (n e Z) ^ (n > 0) 2: if n == 0 then 3: 4: else 5: 6: 7: //LoopInv: 8: while i 2. Consider the following algorithm that attempts to compute the value xn, given an n > 0. Algorithm 6 1: //pre: (n e Z) ^ (n > 0) 2: if n == 0 then 3: 4: else 5: 6: 7: //LoopInv: 8: while i