https://blog.csdn.net/csyifanZhang/article/details/106229805

n个直线/平面/折线能把平面/空间分成几部分？↑

int main() {
	long long T, n;
	cin >> T;
	while (T--) {
		cin >> n;
		cout << n * (n + 1) / 2 + 1 << endl;
	}
}