算法：递归

public class recursion {
    public static void main(String[]args){
        int num=3,n=1,sum=1,l=0;
        //num的阶乘
        for(int i=1;i<=num;i++ ){
            n=n*i;
        }
        System.out.println(n);

        //1-num 阶乘的和
        for(int d=1;d<=num;d++){
            for(int u=1;u<=d;u++){
                sum=sum*u;
            }

            l=l+sum;
                sum=1;

        } System.out.print(l+" ");
    }
}