euler problem 2 (sum even fib sequence < 4m) in clj/cljs

euler2.clj

;; note: the extra case is to fit weird euler def. of fib seq that goes 1, 2, 3, 5, 8, 13, ... rather than 1, 1, 2, 3, 5, 8, 13
;; not nearly as cool as the fibs here: https://en.wikibooks.org/wiki/Clojure_Programming/Examples/Lazy_Fibonacci

(def fib
  (memoize
   (fn [n]
     (case n
       0 0
       1 1
       2 2
       (+ (fib (- n 1)) (fib (- n 2)))))))

(def xf-fib
  (comp
   (map fib)
   (take-while #(<= % 4000000))
   (filter even?)))

(print (transduce xf-fib + (range)))