vl_06_11_2014

gistfile1.clj

(ns repl.freestyle)

(set! *print-length* 50)

(let [r (range 100 -101 -1)]
  [(first r) (last r)])

(let [r (range 0 1002 2)]
  [(first r) (last r)])

(filter even? (range 1002))

(defn sq [x] (* x x))

(take-while (fn [e] (< e 1001)) (map sq (range)))
(drop-while (fn [e] (< e 100)) (range 1 200))

(for [x (range 1 1000)] [x (inc (sq x))])

(let [x (range 10)]
  (for [a x
        b x
        c x :when (< a b c)] [a b c b a]))


(map (fn [[x y _]] [x y])
     (filter (fn [[x y z]] z) (for [x [1 2 3] y [:a :b :c] z [true false]][x y z])))

(frequencies (for [x (range 1 4) y (range 1 4)] (* x y)))

                                        ;// Determine if Mp = 2p − 1 is prime
                                        ;Lucas–Lehmer(p)
                                        ;    var s = 4
                                        ;    var M = 2p − 1
                                        ;    repeat p − 2 times:
                                        ;        s = ((s × s) − 2) mod M
                                        ;    if s = 0 return PRIME else return COMPOSITE

(defn pot [x] (reduce *' 1 (repeat x 2)))

(pot 5)

(defn lamer [p]
  (when (zero?
       (let [M (dec (pot p))]
         (reduce (fn [s _] (-> s sq (- 2) (mod M))) 4 (range (- p 2)))))
    true))

(loop [p 1]
  (println p)
  (when (< p 10) (recur (inc p))))

(defn fakt [n]
  (loop [p n
         c 0]
    (if (even? p)
      (recur (/ p 2) (inc c))
      c)))

(defn perfect? [n]
  (when (<= 2 n)
    (let [
          c (inc (fakt n))
          a (pot (dec c))
          b (dec (pot c))
          ] (and (= n (*  a b)) (lamer c)))))
(perfect? 33550336)

(take 5 (filter perfect? (filter even? (range))))

(def remove-duplicates distinct)