A062070 Smallest base so that n is a square (or 0 if no such base exists).

2, 2, 0, 0, 2, 0, 0, 0, 0, 2, 4, 3, 2, 6, 5, 4, 3, 2, 8, 7, 2, 4, 7, 3, 6, 2, 5, 9, 4, 8, 3, 5, 0, 2, 4, 0, 10, 3, 0, 9, 4, 2, 0, 0, 3, 5, 0, 0, 2, 4, 5, 3, 0, 0, 9, 4, 2, 0, 0, 8, 6, 4, 0, 13, 2, 0, 5, 3, 0, 12, 7, 5, 2, 0, 3, 0, 0, 6, 4, 13, 2, 3, 0, 0, 4, 0, 0, 0, 7, 2, 4, 7, 0, 0, 5, 0, 0, 2, 0, 3, 2