exericse 1.11

exericse-1.11.lisp

(defun calc-f (n)
  (if (< n 3)
      n
    (+ (calc-f (- n 1))
       (* (calc-f (- n 2)) 2)
       (* (calc-f (- n 3)) 3)
       ))
  )

(defun calc-f (n)
  (calc-f-iter 2 1 0 n)
  )

(defun calc-f-iter (a b c count)
  (if (= count 0)
      c
    (calc-f-iter (+ a (* b 2) (* c 3))
                 a
                 b
                 (- count 1))))