From Wikipedia, the free encyclopedia:

 A happy number is defined by the following process:
 Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals   1   (where it will stay),   or it loops endlessly in a cycle which does not include   1.   


 Those numbers for which this process end in   1   are       happy   numbers,   
 while   those numbers   that   do   not   end in   1   are   unhappy   numbers. 


Task

Find and print the first   8   happy numbers.

Display an example of your output here on this page.



See also

   The OEIS entry:   The     happy numbers:   A007770
   The OEIS entry:   The unhappy numbers;   A031177


(defn happy? [n]
  (loop [n n, seen #{}]
    (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)))
 
(println (take 8 happy-numbers))