About nothing

Here's a way to quickly compute the leftmost digit of a number:

(define (leftmost-digit radix n)
  (if (> radix n)
      n
      (let ((leftmost-digit-pair (leftmost-digit (* radix radix) n)))
 (if (> radix leftmost-digit-pair)
     leftmost-digit-pair
     (quotient leftmost-digit-pair radix)))))

It's harder to compute the remaining digits.