Cube number

A cube number or perfect cube is a positive integer of the form n3 where n is a positive integer.

Examples
The first 20 cube numbers are:

1, 8, 27, 64, 125 216, 343, 512, 729, 1000 1331, 1728, 2197, 2744, 3375 4096, 4913, 5832, 6859, 8000