(defn three-or-five [num]
  (if (== (mod num 5) 0)
    5
    (if (== (mod num 3) 0)
      3
      0)))

(defn produce-list [range]
  (loop [current 0, total 0]
    (if (== current range)
      total
      (recur (+ current 1) (+ total (three-or-five current))))))

(def num-total (produce-list 1000))