gistfile1.scala

// Sieve of Eratosthenes
def calc_primes( nums:List[Int] ):List[Int] = {
    nums match {
        case x::xs =>
            val nums_dash = for( i <- xs if i % x != 0 ) yield i
            println( Runtime.getRuntime.totalMemory/1024/1024 )
            x :: calc_primes( nums_dash )
        case _ => Nil
    }
}

val res = calc_primes( (2 to 100000).toList ) // java.lang.OutOfMemoryError: Java heap space
println( res.size )