A074954 Least perfect power b^e such that b^e-n is also a perfect power, or 0 if no such perfect power exists.

9, 27, 4, 8, 9, 0, 8, 9, 25, 2197, 27, 16, 49, 0, 16, 25, 25, 27, 27, 36, 25, 49, 27, 25, 125, 27, 36, 32, 225, 6889, 32, 36, 49, 0, 36, 100, 64, 1369, 64, 49, 49, 0, 484, 125, 49, 289, 128, 49, 81, 0, 100, 196, 729, 81, 64, 64, 121, 0, 900, 64, 125, 0, 64, 100, 81, 0, 1156