Proof: We can use Lemma 1. It follows that c = a + b-j. Hence y = 2 or 4. Case y = 2: In this case we have a = 2 + ^rj. Thus b-2 = ±1, ±2, so fc = 1, 3, 0, 4 giving a = 0, 4, 1, 3. Hence, {a, b} = {4, 3} or {3, 4}, and we have the 3-4-5 triangle. Case y = 4: In this case we have a-1 + 2(ft '_ t). Clearly, there are no integer solutions to this equation.