base 13 is a positional numeral system with thirteen as its base. It uses 13 different digits for representing numbers. The digits for base 13 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, and c.
quaternary (base 4)
Quaternary is the base-4 numeral system. It uses the digits 0, 1, 2 and 3 to represent any real number.