代碼：
1 import java.util.*; 2 public class Main { 3 public static void main (String [] args) { 4 Scanner scan=new Scanner(System.in); 5 int n=scan.nextInt(); 6 int sum=0; 7 for(int i=1;i<=n;i++) { 8 int p=1; 9 for(int j=1;j<=i;j++) { 10 p*=j; 11 } 12 sum+=p; 13 } 14 System.out.println(sum); 15 } 16 }