val power Int Int Int case if case if power n-1 case power power

val power: Int => (Int => Int) = 
	n => {
    	case x if (n == 0) => 1
        case x if (n%2 == 1) => power(n-1)(x) * x
        case x => power(n/2)(x) * power(n/2)(x)
}