Egyptian fractions in Clojure

gistfile1.clj

(ns ef
 (:require [clojure.math.numeric-tower :as nt]))

(defn ef [r]
 (loop [r r ef []]
  (let [x (numerator r)
        y (denominator r)]
   (if (= x 1) (conj ef r)
               (recur (/ (mod (- y) x) (* y (nt/ceil (/ y x))))
                      (conj ef (/ (nt/ceil (/ y x)))))))))

(defn ef-lazy [r]
  (let [x (numerator r)]
    (if (= x 1) (list r)
                (let [y (denominator r)
                      z (nt/ceil (/ y x))]
                  (cons (/ z) (lazy-seq (ef-lazy (/ (mod (- y) x) (* y z)))))))))

(defn ef-max-denom [r]
  (-> r ef-lazy last denominator))

(first (reduce (partial max-key second)
               (map (juxt identity ef-max-denom)
                    (for [d (range 1 100) n (range 1 d)] (/ n d)))))
;=> 8/97