1. 位数等于输入得数大小。
  2. 如果是奇数得话,平方一定在中间,然后算出最左边就可以(start = mid- num/2 2;)。如果偶数的话(start = mid- (2 num/2 -1);)
#include<bits/stdc++.h>

using namespace std;

int main(){

    int num;

    while(cin>>num){

         int flag = 0;
         if(num&1){
            flag = 1;
         }

        int mid = pow(num,2);
        int z =0;
        int start = 0;

        if(flag){

            start = mid-  num/2 *2;

        }else{

            start = mid-  (2* num/2 -1);

        }


        for(int i=0; i< num;i++){

           if(i==num-1){
               cout<<start + i*2<<endl;
           }else{
                cout<<start + i*2<<"+";
           }


        }



    }


    return 0;
}