Quaternary is the base-4 numeral system. It uses the digits 0, 1, 2 and 3 to represent any real number.
base 20
base 20 is a positional numeral system with twenty as its base. It uses 20 different digits for representing numbers. The digits for base 20 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f, g, h, i, and j.