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: //package contests.div2.c750;
  
  import java.io.*;
  import java.util.StringTokenizer;
  
  public class B {
  
  
      static PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
  
      static int fasterScanner() {
          try {
              boolean in = false;
              int res = 0;
              for (; ; ) {
                  int b = System.in.read() - '0';
                  if (b >= 0) {
                      in = true;
                      res = 10 * res + b;
                  } else if (in) {
                      return res;
                  }
              }
          } catch (IOException e) {
              throw new Error(e);
          }
      }
  
      public static void main(String[] args) {
          FastScanner sc = new FastScanner();
          int t = fasterScanner();
          while (t-- > 0) {
              int n = fasterScanner();
              int cnt0 = 0, cnt1 = 0;
              for (int i = 0; i < n; i++) {
                  long num = fasterScanner();
                  if (num == 1) {
                      cnt1++;
                  } else if (num == 0) {
                      cnt0++;
                  }
              }
              out.println((long) Math.pow(2, cnt0) * cnt1);
          }
          out.close();
      }
  
      static class FastScanner {
  
          BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
          StringTokenizer st = new StringTokenizer("");
  
          String next() {
              while (!st.hasMoreTokens()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  } catch (IOException e) {
                  }
              }
              return st.nextToken();
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
  
          long nextLong() {
              return Long.parseLong(next());
          }
      }
  }
  