Codeforces Round #638 (Div. 2), problem: (A) Phoenix and Balance

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int t;
	cin >> t;
	while(t--)
	{
		int n;
		cin >> n;
		int sum = 0;
		for(int i=1;i<=n/2-1;i++)
		sum += (int)pow(2,i);
		sum += (int)pow(2,n);
		int sum2 =0;
		for(int i=n/2;i<n;i++)
		sum2+=(int)pow(2,i);
		int diff = abs(sum-sum2);
		cout << diff << "\n";
	}
}