* largest @size_t@ value. Then the largest possible @mp@ is %$M - 1$% where
* %$M = b^Z$%. Let %$r$% be a radix to read or write. Since the recursion
* squares the radix at each step, the highest number reached by the
* largest @size_t@ value. Then the largest possible @mp@ is %$M - 1$% where
* %$M = b^Z$%. Let %$r$% be a radix to read or write. Since the recursion
* squares the radix at each step, the highest number reached by the