gistfile1.lisp

(setq used (make-array 9 :initial-element t)
          answer ()
          permutation (make-array 9))

(defun number (l r)
  (do ((i l (1+ i)) (ret 0)) ((= i r) ret)
        (setq ret (+ (* ret 10) (aref permutation i)))))

(defun doIt ()
  (do ((r 2 (1+ r))) ((= r 9))
        (do ((l 1 (1+ l))) ((= l r))
          (if (= (number r 9) (* (number 0 l) (number l r)))
                  (setq answer (cons (number r 9) answer))))))

(defun make-permutation (k)
  (if (= k 9)
          (doIt)
        (dotimes (x 9)
          (cond ((aref used x)
                         (setf (aref used x) nil)
                         (setf (aref permutation k) (1+ x))
                         (make-permutation (1+ k))
                         (setf (aref used x) t))))))

(make-permutation 0)

(setq answer (reduce #'+ (remove-duplicates answer)))

(print answer)
; => 45228