description: Luntik came out for a morning stroll and found an array a of length n. He calculated the sum s of the elements of the array (s= ∑_{i=1}^{n} a_i). Luntik calls a subsequence of the array a nearly full if the sum of the numbers in that subsequence is equal to s-1.
  
  Luntik really wants to know the number of nearly full subsequences of the array a. But he needs to come home so he asks you to solve that problem!
  
  A sequence x is a subsequence of a sequence y if x can be obtained from y by deletion of several (possibly, zero or all) elements.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of test cases. The next 2 ⋅ t lines contain descriptions of test cases. The description of each test case consists of two lines.
  
  The first line of each test case contains a single integer n (1 ≤ n ≤ 60) — the length of the array.
  
  The second line contains n integers a_1, a_2, …, a_n (0 ≤ a_i ≤ 10^9) — the elements of the array a.
  
  Output
  
  For each test case print the number of nearly full subsequences of the array.
  
  Example
  
  Input
  
  
  5
  5
  1 2 3 4 5
  2
  1000 1000
  2
  1 0
  5
  3 0 2 1 1
  5
  2 1 0 3 0
  
  
  Output
  
  
  1
  0
  2
  4
  4
  
  Note
  
  In the first test case, s=1+2+3+4+5=15, only (2,3,4,5) is a nearly full subsequence among all subsequences, the sum in it is equal to 2+3+4+5=14=15-1.
  
  In the second test case, there are no nearly full subsequences.
  
  In the third test case, s=1+0=1, the nearly full subsequences are (0) and () (the sum of an empty subsequence is 0).
solution: 
  // import java.util.StringTokenizer;
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.StringTokenizer;
  
  public class B {
      static BufferedReader br;
      static double pre = 1e-9;
      static long mod = (long) (1e+9 + 7);
      static boolean isPrime[];
  
      public static void main(String[] args) throws IOException {
          // your code goes here
  
          br = new BufferedReader(new InputStreamReader(System.in));
          int t = Integer.parseInt(br.readLine());
  
          // B
          while (t-- > 0) {
              int n = Integer.parseInt(br.readLine());
              StringTokenizer st;
              long count1 = 0, count0 = 0;
  
              st = new StringTokenizer(br.readLine());
              for (int i = 0; i < n; i++) {
                  int num = Integer.parseInt(st.nextToken());
                  if (num == 0) {
                      count0++;
                  }
                  if (num == 1) {
                      count1++;
                  }
              }
              long ans = (long) Math.pow(2, count0) * count1;
  
              System.out.println(ans);
          }
  
      }
  
      private static long max3(long a, long b, long c) {
          if (a > b) {
              if (a > c) {
                  return a;
              }
              return c;
          }
          if (b > c) {
              return b;
          }
          return c;
      }
  
      private static long binStringToNumMod(String str, long n, long mod) {
          long ans = 0;
          for (int i = 0; i < str.length(); i++) {
              ans = ((ans * n) % mod + (Integer.parseInt(str.substring(i, i + 1))) % mod) % mod;
          }
          return ans;
      }
  
      private static String numToBinString(long num) {
          StringBuffer sb = new StringBuffer("");
          while (num > 0) {
              sb.append(num % 2);
              num /= 2;
          }
          return sb.reverse().toString();
      }
  
      public static boolean[] SieveOfEratosthenes() {
          int n = (int) 1e7 + 7;
          boolean[] ans = new boolean[n];
          Arrays.fill(ans, true);
          ans[0] = false;
          ans[1] = false;
          for (int i = 2; i < n; i++) {
              if (ans[i]) {
                  for (int j = i * i; j < n; j = j + i) {
                      ans[j] = false;
                  }
              }
          }
          return ans;
  
      }
  
      public static long powerMod(long num, long pow, long mod) {
          if (pow == 0 || num == 1)
              return 1;
          if (num == 0 || pow == 1)
              return num;
  
          long ans = powerMod(num, pow / 2, mod) % mod;
  
          ans = (ans * ans) % mod;
  
          if (pow % 2 != 0) {
              ans = (ans * num) % mod;
          }
  
          return ans;
      }
  
      public static long gcd(long a, long b) {
          if (b == 0 || a == b)
              return a;
          if (a == 1 || b == 1)
              return 1;
          return gcd(b, a % b);
  
      }
  
      static class Element implements Comparable<Element> {
          int num;
          int freq;
  
          Element(int num, int freq) {
              this.num = num;
              this.freq = freq;
          }
  
          public int compareTo(Element e) {
              if (this.freq > e.freq) {
                  return 1;
              }
              if (this.freq == e.freq) {
                  return 0;
              }
              return -1;
          }
      }
  
  }
  