Prove that this sequence is well defined. That is, show that a(n) is uniquely defined for all nonnegative integers n.
Deal with some unusual sequences, informally called self-generating sequences, produced by simple recurrence relations or rules. In particular, Exercises 70-75 deal with the sequence {a(n)} defined by a(n) = n − a(a(n − 1)) for n ≥ 1 and a(0) = 0. (This sequence, as well as those in Exercises 74 and 75, are defined in Douglas Hofstader's fascinating book Gödel, Escher, Bach ([Ho99]).