In C# :

using System; using System.Numerics;

class Solution { static void Main(string[] args) { int t = Convert.ToInt32(Console.ReadLine());

    while (t-- > 0)
    {
        int n = Convert.ToInt32(Console.ReadLine());

        BigInteger pow = BigInteger.One;

        for (int i = 1; i <= n; i++)
        {
            pow = BigInteger.Multiply(pow, new BigInteger(2));
        }

        int sum = 0;
        while (pow > 0)
        {
            BigInteger d = pow % 10;
            sum += (int)d;

            pow /= 10;
        }

        Console.WriteLine(sum);
    }
}

}