FizzBuzz...

using-case.lisp

(defun fizzbuzz (n)
  (fizzbuzz-helper 1 n ))

(defun fizzbuzz-helper (n x)
  (case (mod n 15)
    (0 (princ "FizzBuzz"))
    ((3 6 9 12) (princ "Fizz"))
    ((5 10) (princ "Buzz"))
    (otherwise (princ n)))
  (fresh-line)
  (if (< n x)
    (fizzbuzz-helper (+ 1 n) x)))

using-cond.lisp

(defun fizzbuzz (n)
  (fizzbuzz-helper 1 n ))

(defun fizzbuzz-helper (n x)
  (cond 
    ((= 0 (mod n 15)) (princ "FizzBuzz"))
    ((= 0 (mod n 3)) (princ "Fizz"))
    ((= 0 (mod n 5)) (princ "Buzz"))
    (otherwise (princ n)))
  (fresh-line)
  (if (< n x)
    (fizzbuzz-helper (+ 1 n) x)))