Generating a sequence corresponding to an infinite breadth-first tree traversal

BreadthTree.clj

(def atoms '("a" "b" "c"))

(defn get-children [n] (map #(str n %) atoms))

(defn add-layer
  ([] (add-layer atoms))
  ([n] 
    (let [child-nodes (flatten (map get-children n)) ]
      (lazy-seq (concat n (add-layer child-nodes))))))