Project Euler Problem 9

Problem009.clj

;;; A Pythagorean triplet is a set of three natural numbers, a  b  c, for which,
;;; a^2 + b^2 = c^2
;;; For example, 3^2 + 4^2 = 9 + 16 = 25 = 5^2.
;;; There exists exactly one Pythagorean triplet for which a + b + c = 1000.
;;; Find the product abc.

(defn problem9 [limit]
  (let [lazy-seq (take limit (iterate inc 1))]
    (for [a lazy-seq b lazy-seq c lazy-seq
          :when (and (= (+ (* a a) (* b b)) (* c c))
                     (= (+ a b c) 1000))]
      [:a a :b b :c c :product (* a b c)])))
(problem9 500)
;;;=> [:a xxx :b xxx :c xxx :product xxx(ans)]