Happy New Year 2015

happy-new-year-2015.clj

;; https://sites.google.com/site/unclebobconsultingllc/home/articles/clojure-prime-factors
(defn factors [n]
  (let [candidates (range 1 (inc n))]
    (filter #(zero? (rem n %)) candidates)))

(defn prime? [n] 
  (or (= n 2)
      (= 2 (count (take 3 (factors n))))))

(defn prime-factors [n]
  (filter prime? (factors n)))

;; Get prime factors for number 2015
(prime-factors 2015)
;; => (5 13 31)

;; Using only these factors (5 13 31), construct numbers
[(- 13 5) (- 31 (* 5 5) 5) (+ 13 (- 13 5 5)) (+ 13 (- 13 5 5)) (* 5 5) (- (- 31 (* 5 5) 5) (* 13 5)) (+ 13 (- 31 (* 5 5) 5)) 5 (+ 13 5 5) (- (- 31 (* 5 5) 5) (* 13 5)) (* 5 5) 5 (- 31 (* 5 5) 5) (+ 13 5)]
;; => [8 1 16 16 25 -64 14 5 23 -64 25 5 1 18]

;; Get 96
(+ 31 (* 5 13))
;; => 96

;; Some manipulations
(->> [8 1 16 16 25 -64 14 5 23 -64 25 5 1 18]
     (map #(+ 96 %), )
     (map char, )
     (map str, )
     (apply str, ))
;; => "happy new year"