#include <iostream>
#include <stdio.h>

using namespace std;

int main(void){
  int a_1 = 2;
  int x;
  int s;
  cin >> x;

  while(scanf("%d", &x) != EOF ){
    if(x == 1){
      cout << a_1;
    }else{
      s += a_1;
      for(int i = 1; i <= x; i++){
        s += i;
      }
    }
  }

}
