euler002.clj

; Problem 2:
; Find the sum of all the even-valued terms in the Fibonacci
; sequence which do not exceed four million.

(defn nextfib [[x y]]
  (cond (zero? x) [1 1]
	:else [y (+ x y)]))
(def fibs (map first (iterate nextfib [0 nil])))
(def even-fibs-lt-4mil 
	    (filter even? 
		    (take-while #(< % 4000000 ) fibs)))
(apply + even-fibs-lt-4mil)