;faktorial

(defun fact (n)
       (cond ((= n 1) 1)
             (t (* n (fact (- n 1))))))

;----------------
;fibonacci
; fib (0) = 0
; fib (1) = 1
; fib (n) = fib (n-1) + fib (n-2)
 
(defun fib (n)
 (if (< n 2)
    n
    (+ (fib (- n 1)) (fib (- n 2)))))

 
;ackermanova fce
;m >= 0, n >= 0
;ack(0, n) = n+1
;ack(m, 0) = ack(m-1, 1)
;ack(m, n) = ack(m-1, ack(m, n-1))

(defun ack (m n)
  (cond
   ((zerop m) (1+ n))
   ((zerop n) (ack (1- m) 1))
   (t (ack (1- m) (ack m (1- n))))))