啊题解

#include<bits/stdc++.h>
using namespace std;
int main(){
int n;
cin >> n;
while(n--) {
int k;
cin >> k;
long long a[10010] = {};
a[1] = 2;
for(int i = 2; i <= k; i++) {
a[i] = a[i - 1] + i;
}
cout << a[k] << endl;
}
return 0;
}