题解 | #尼科彻斯定理#

#include <stdio.h>

int main() {
    int n = 0;
    scanf("%d",&n);
   
        printf("%d",n*n-(n-1));
        for(int i =1;i<n;i++)
        {
            printf("+%d",n*n-(n-1)+2*i);
        }  
}