#include <stdio.h>
int main() {
//求1!+2!+3!+4!+…+20!
unsigned long long num = 1;
unsigned long long sum = 0;
for(int i =1;i<=20;i++){
num *= i;
sum += num;
}
printf("%llu",sum);
return 0;
}
#include<stdio.h> long long int f(int n) { long long int sum; if (n == 0 || n == 1) sum = 1; else sum = f(n - 1) * n; return (sum); } int main() { long long int f(int n); int n,i; long long int sum = 0; scanf("%d", &n); for (i = 1; i <= n; i++) { sum += f(i); } printf("%lld\n", sum); return 0; }
#include <stdio.h> int factory(int n){ int k = 1; for(int i = 1; i <= n; i ++){ k *= i; } return k; } int main(){ int n; scanf("%d", &n); int cnt = 0; for(int i = 1; i <= n; i ++){ cnt += factory(i); } printf("%d", cnt); }