(defn prime-factors [n]
  (loop [nums (cons 2 (iterate #(+ 2 %) 3))
         factors []
         v n]
    (let [f (first nums)]
    (cond
      (= v 1) factors
      (= 0 (mod v f)) (recur nums (conj factors f) (quot v f))
      :else (recur (rest nums) factors v)))))
;(loop [i 1]
;  (when (< i 100)
;    (println i (prime-factors i))
;    (recur (inc i))))
(println 123 (prime-factors 123))