12_factorial_while.el

(defun factorial (n)
  (let ((accum 1))
    (while (> n 0)
           (setq accum (* accum n))
           (setq n (1- n)))
    accum))

(setq n 0)
(while (< n 15)
       (print (factorial n))
       (setq n (1+ n)))