Factorial in Lisp

Example for versions Clojure 1.0.0, Clojure 1.1.0

This example uses recursive factorial definition. range with one argument generates a list of numbers from 0 (inclusive) to this number (exclusive). str concatenates strings. dec is decrement, equivalent to (- x 1). doseg is Clojure-style loop. 

(defn factorial [x]
  (if (< x 2)
    1
    (* x (factorial (dec x)))))

(doseq [i (range 17)]
  (println (str (str i "! = ") (factorial i))))