Base 58 to Base 20

Base 58

In base 58, each digit position represents a power of 58: the rightmost digit counts individual ones, the next counts groups of 58, the next counts groups of 58×58, and so on — the same place-value idea as base 10, just with 58 distinct digits instead of ten.

Base 20

Base 20 works the same way: the rightmost digit counts ones, the next counts groups of 20, the next counts groups of 20×20, and so on, using 20 distinct digits.