factorial.lisp

(defun factorial (n)
  (if (<= n 1)
    1
    (* n (factorial  (- n 1)))))
    
(dotimes (x 10)
  (let ((n (+ x 1))) 
    (format t "factorial ~2D = ~D~%" n (factorial  n))))
    
; output
; factorial  1 = 1
; factorial  2 = 2
; factorial  3 = 6
; factorial  4 = 24
; factorial  5 = 120
; factorial  6 = 720
; factorial  7 = 5040
; factorial  8 = 40320
; factorial  9 = 362880
; factorial 10 = 3628800