这个怎么用for循环做，求解

Question

Answer 1

#include<stdio.h>
int main(){
int n,sum=0;
scanf("%d",n);
for(int i=1; i < n; i++){
sum += (2*n-1)(2*n+1)/(2*n);
}
printf("计算值为:%d\n", sum);
return 0;
}