Collatz algorithm in Scala and Clojure

collatz.clj

(defn 
  #^{:doc "Clojure code to compute a Collatz sequence."}
  collatz [n] 
  (if (= n 1) 
      '(1) 
      (cons n 
            (collatz (if (= (mod n 2) 0) 
                         (/ n 2) 
                         (+ (* n 3) 1))))))

collatz.scala

/**
 * Scala code to compute a Collatz sequence.
 * See http://en.wikipedia.org/wiki/Collatz_conjecture
 */
def collatz(n:BigInt):Stream[BigInt] =
  if (n == 1) {
     Stream(1);
  } else {
     def next(n:BigInt):BigInt = if ((n % 2) == 0) (n / 2) else (n * 3 + 1);
     Stream.cons(n, collatz(next(n)));
  }

/**
 * Using match.
 */

import scala.math.BigInt

def collatz(number: BigInt): Stream[BigInt] = number match {
  case n if n == 1 => Stream(1)
  case n if n % 2 == 0 => Stream.cons(number, collatz(number / 2))
  case _ => Stream.cons(number, collatz(number * 3 + 1))
}