The fact that it's using lookup tables to store the mapping between the set of numbers and the encoded 16-bit number makes it less interesting; it basically jus

The fact that it's using lookup tables to store the mapping between the set of numbers and the encoded 16-bit number makes it less interesting; it basically just enumerates the set of all possible combinations of numbers, and uses the ordinal as the encoding. A directly calculated scheme without a lookup would be niftier, though I suspect in practice the way it steals bits from redundancy of duplicates it wouldn't be pretty.