(loop for i of-type fixnum in '(1 2 3 4 5)
       sum i)
⇒  15
 (setq series '(1.2 4.3 5.7))
⇒  (1.2 4.3 5.7)
 (loop for v in series 
       sum (* 2.0 v))
⇒  22.4