计算某数值以下的偶数fib和

sum-even-fib.clj

(def fib-seq
        (lazy-cat [0 1] (map + (rest fib-seq) fib-seq)))


(def even-fib-seq (filter even? fib-seq))

(defn sum-fib [limit]
    (loop [i 1
           fib-num (nth even-fib-seq i)
           seqn []]
        (if (>= fib-num limit)
             (apply + seqn)
             (recur (inc i) (nth even-fib-seq (inc i)) (cons fib-num seqn )))))