水题，题不难，找公式难

import java.math.BigInteger;

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner input=new Scanner(System.in);

		int n=input.nextInt();

		while(n-->0){

			int k =input.nextInt();

			System.out.println(BigInteger.valueOf(4).pow(k).subtract(BigInteger.ONE).divide(BigInteger.valueOf(3)));

		}

	}

}