collatz.lisp

(defun collatz (n)
  (labels ((internal (n lst)
                     (cond
                       ((= n 1) (cons n lst))
                       ((evenp n) (internal (/ n 2) (cons n lst)))
                       ((oddp n)
                        (internal (+ (* 3 n) 1) (cons n lst))))))
    (internal n '())))

(defun list-to-gv (lst)
  (labels ((internal (lst lastn)
                     (cond ((equalp lst nil) lst)
                           (t
                             (if (equalp lastn nil)
                               nil
                               (format t "~d -> ~d;~%" (car lst) lastn))
                             (internal (cdr lst) (car lst))))))
    (internal lst nil)))