書き初め@2015

collatz.scm

#!/usr/local/bin/gosh


(define (collatz-next n)
  (cond
    ((even? n) (/ n 2))
    ((odd? n) (+ (* n 3) 1)))
  )

(define (collatz n)
  (if (<= n 1) '(1)
      (cons n (collatz (collatz-next n)))
      )
    )

(define (main args)
  (print (collatz 2015))
  0 )