Exercise
Let a be an integer greater than 3. Is (1331)a a cube?
No, it is not
Yes, it is the cube of (11)a
No, not always, a should be odd.
What is the cube root of 1331 in the decimal system?
Indeed, since (11)a = (a + 1) and (a + 1)3 = a3+ 3a2 + 3a + 1.
What is the cube root of 1331 in the decimal system?