(setq A '(1 2 3 4 5))

(setq B '())

(defun caesar (X Y d)
 (if (CDR X)
      (proc
       (caesar (CDR X) Y d)
       (CONS '(+ (CAR X) d) 'Y)
      )
     (CONS '(+ (CAR X) d) 'Y)
 )
)

(caesar A B 3)
(B)