My second FooBarQix (http://www.code-story.net/2011/11/16/foobarqix.html) solution

foobarqix.cl

(setq *fbq* (make-hash-table))
(setf (gethash 3 *fbq*) "Foo")
(setf (gethash 5 *fbq*) "Bar")
(setf (gethash 7 *fbq*) "Qix")

(defun foo (v) (
                let ((div ""))
                (maphash #'(lambda (key value)
                             (cond ((= (mod v key) 0)
                                    (setf div (concatenate 'string value div))
                                    ))  
                             )   
                         *fbq*)
                div 
                ))  

(defun bar (v) (
                let ((rep ""))
                (map 'string #'(lambda (c) 
                                 (setf k (gethash (parse-integer (string c)) *fbq*))
                                 (if (not (null k)) 
                                   (setf rep (concatenate 'string rep k)) 
                                   )   
                                 c   
                                 )   
                     (write-to-string v)) 
                rep 
                ))

(defun qix (v) (
                let ((result (concatenate 'string (foo v) (bar v))))

                (if (= 0 (length result)) 
                  (setf result (write-to-string v)) 
                  )   
                result
                ))  

(loop for i from 1 to 100 do (format t "~D : ~A~%" i (qix i)))