Just another update

Task/Happy-numbers/Clojure/happy-numbers.clj

@@ -1,13 +1,14 @@
-(defn- digit-to-num [d] (Character/digit d 10))
-(defn- square [n] (* n n))
-
 (defn happy? [n]
   (loop [n n, seen #{}]
-    (cond (= n 1)  true
-          (seen n) false
-          :else
-          (recur (reduce + (map (comp square digit-to-num) (str n)))
-                 (conj seen n)))))
+    (cond
+      (= n 1)  true
+      (seen n) false
+      :else
+        (recur (->> (str n)
+                    (map #(Character/digit % 10))
+                    (map #(* % %))
+                    (reduce +))
+               (conj seen n)))))
 
 (def happy-numbers (filter happy? (iterate inc 1)))