A lazy sequence of the Pythagorean Triples.

PythTrips.clj

(defn t1
  [[a b c]]
  [($=  1 * a - 2 * b + 2 * c)
   ($=  2 * a - 1 * b + 2 * c)
   ($=  2 * a - 2 * b + 3 * c)])

(defn t2
  [[a b c]]
  [($=  1 * a + 2 * b + 2 * c)
   ($=  2 * a + 1 * b + 2 * c)
   ($=  2 * a + 2 * b + 3 * c)])

(defn t3
  [[a b c]]
  [($= -1 * a + 2 * b + 2 * c)
   ($= -2 * a + 1 * b + 2 * c)
   ($= -2 * a + 2 * b + 3 * c)])

(defn ts
  [abc]
  [(t1 abc) (t2 abc) (t3 abc)])

(defn lazy-mapcat
  [f coll]
  (lazy-seq
    (if (not-empty coll)
      (concat
        (f (first coll))
        (lazy-mapcat f (rest coll))))))

(def pythTrips
  (lazy-cat [[3 4 5]] (lazy-mapcat ts pythTrips)))