class Recursive{
    public static double eval( int n){
        if (n==0) { 
            return 1.0;
        }else{ 
            double sum = 0.0;
            for (int i = 0; i < n; i++){
                sum = sum + eval(i);
            }
            return 2.0 * sum/n + n;
        }
    }
}