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euler / clojure / 2.clj

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; 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.
;
; Answer: 4613732

(defn fibs []
 (map first (iterate (fn [[a b]] [b (+ a b)]) [1 1])))

(println (apply + (take-while #(< % 4000000) (filter even? (fibs)))))