Bus Solution:

#include <bits/stdc++.h>
using namespace std;

int main(){
    // #ifndef TESTING
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    // #endif

    int cases;
    cin >> cases;
    int k;
    cout << setprecision(20);
    while(cases--){
        cin >> k;
        cout << pow(2, k) - 1 << endl;
    }

    return 0;
}