Base-6 (also called senary or heximal or seximal) number system uses six symbols to code information. Most commonly, these symbols are, 0, 1, 2, 3, 4 and 5.
Base-16 (also known as hexadecimal) number system uses 16 symbols to code information. Most commonly, these symbols are, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 'A to F' (or alternatively 'a to f').