lucky.clj

(ns miner.lucky
  (:require [clojure.data.avl :as avl]))
     
;; http://en.wikipedia.org/wiki/Lucky_number

(defn lucky-avl
  ([max] (lucky-avl 1 (apply avl/sorted-set (range 1 max 2))))
  ([i avl]
   (let [n (nth avl i nil)]
     (if (and n (<= n (count avl)))
       (recur (inc i) (reduce (fn [sss m] (disj sss (nth avl m)))
                              avl
                              (range (dec n) (count avl) n)))
       (sequence avl)))))