;; Each new term in the Fibonacci sequence is generated by adding 
;; the previous two terms. By starting with 1 and 2, the first 10 
;; terms will be:
;;
;;     1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...

;; Find the sum of all the even-valued terms in the sequence which 
;; do not exceed four million.

(def lazy-fibo
  (lazy-cat [1 2] (map + lazy-fibo (rest lazy-fibo))))

(defn less-than-4-million? [n] (< n 4000000))
	
(defn euler-2-v0 []
  (reduce + (filter even? (take-while less-than-4m lazy-fibo))))