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.*;
  import java.lang.*;
  import java.io.*;
  public class Main  
  {
      static FastReader sc =new FastReader();
      static PrintWriter out=new PrintWriter(System.out);
      static int mod=10000007;
      
         public static void main(String [] args)
      {
          int t = i();
          while(t-->0)
          {
              int n = i();
              long a[] = inputL(n);
              long sum = 0,cnt=0,cnt2=0,ans=0;
              for(int i=0;i<n;i++)
              {
                  if(a[i]==0)
                  cnt++;
                  if(a[i]==1)
                  cnt2++;
              }
              
              ans = power(2, cnt);
              ans*=cnt2;
              
              out.println(ans);
              
          }
          
          out.close();
      }
     
    
      static class FastReader 
      { 
          BufferedReader br; 
          StringTokenizer st; 
  
          public FastReader() 
          { 
              br = new BufferedReader(new
                       InputStreamReader(System.in)); 
          } 
  
          String next() 
          { 
              while (st == null || !st.hasMoreElements()) 
              { 
                  try
                  { 
                      st = new StringTokenizer(br.readLine()); 
                  } 
                  catch (IOException  e) 
                  { 
                      e.printStackTrace(); 
                  } 
              } 
              return st.nextToken(); 
          } 
  
          int nextInt() 
          { 
              return Integer.parseInt(next()); 
          } 
  
          long nextLong() 
          { 
              return Long.parseLong(next()); 
          } 
  
          double nextDouble() 
          { 
              return Double.parseDouble(next()); 
          } 
  
          String nextLine() 
          { 
              String str = ""; 
              try
              { 
                  str = br.readLine(); 
              } 
              catch (IOException e) 
              { 
                  e.printStackTrace(); 
              } 
              return str; 
          } 
      } 
  
      static int i() {
          return sc.nextInt();
      }
  
      static String s() {
          return sc.next();
      }
  
      static long l() {
          return sc.nextLong();
      }
  
      static char[] inputC()
      {
          String s = sc.nextLine();
          return s.toCharArray();
      }
  
      static int[] input(int n) {
          int A[]=new int[n];
             for(int i=0;i<n;i++) {
                 A[i]=sc.nextInt();
             }
          return A;
      }
  
      static long[] inputL(int n) {
          long A[]=new long[n];
             for(int i=0;i<n;i++) {
                 A[i]=sc.nextLong();
             }
             return A;
      }
  
      static long[] putL(long a[]) {
          long A[]=new long[a.length];
             for(int i=0;i<a.length;i++) {
                 A[i]=a[i];
             }
             return A;
      }
  
      static String[] inputS(int n) {
          String A[]=new String[n];
             for(int i=0;i<n;i++) {
                 A[i]=sc.next();
             }
             return A;
      }
        
      static int gcd(int a, int b) 
       { 
           if (a == 0) 
               return b; 
           return gcd(b % a, a); 
       } 
  
       static long gcd(long a, long b) 
       { 
           if (a == 0) 
               return b; 
           return gcd(b % a, a); 
       } 
  
       
      
       static String reverse(String s) {
          StringBuffer p=new StringBuffer(s);
          p.reverse();
          return p.toString();
       }
  
       static int min(int a,int b) {
          return Math.min(a, b);
      }
      static int min(int a,int b,int c) {
          return Math.min(a, Math.min(b, c));
      }
      static int min(int a,int b,int c,int d) {
          return Math.min(a, Math.min(b, Math.min(c, d)));
      }
  
      static int max(int a,int b) {
          return Math.max(a, b);
      }
      static int max(int a,int b,int c) {
          return Math.max(a, Math.max(b, c));
      }
      static int max(int a,int b,int c,int d) {
          return Math.max(a, Math.max(b, Math.max(c, d)));
      }
      static long min(long a,long b) {
          return Math.min(a, b);
      }
      static long min(long a,long b,long c) {
          return Math.min(a, Math.min(b, c));
      }
      static long min(long a,long b,long c,long d) {
          return Math.min(a, Math.min(b, Math.min(c, d)));
      }
      static long max(long a,long b) {
          return Math.max(a, b);
      }
      static long max(long a,long b,long c) {
          return Math.max(a, Math.max(b, c));
      }
      static long max(long a,long b,long c,long d) {
          return Math.max(a, Math.max(b, Math.max(c, d)));
      }
  
      static long sum(int A[]) {
          long sum=0;
          for(int i : A) {
              sum+=i;
          }
          return sum;
      }
  
      static long sum(long A[]) {
          long sum=0;
          for(long i : A) {
              sum+=i;
          }
          return sum;
      }
  
      static void print(int A[]) {
          for(int i : A) {
              System.out.print(i+" ");
          }
          System.out.println();
      }
  
      static void print(long A[]) {
          for(long i : A) {
              System.out.print(i+" ");
          }
          System.out.println();
      }
  
      static long mod(long x) {
            return ((x%mod + mod)%mod);
      }
  
      static long power(long x, long y)
      {
  
  	if(y==0)
  		return 1;
  	if(x==0)
  		return 0;
      long res = 1;
      while (y > 0) {
  
          if (y % 2 == 1)
              res = (res * x) ;
  
          y = y >> 1; 
          x = (x * x);
      }
  
      return res;
      }
  
      static boolean prime(int n) 
  	    { 
  	        if (n <= 1) 
  	            return false; 
  	        if (n <= 3) 
  	            return true; 
  	        if (n % 2 == 0 || n % 3 == 0) 
  	            return false; 
  	        double sq=Math.sqrt(n);
  	  
  	        for (int i = 5; i <= sq; i = i + 6) 
  	            if (n % i == 0 || n % (i + 2) == 0) 
  	                return false; 
  	        return true; 
  	    } 
  
       static boolean prime(long n) 
  	    { 
  	        if (n <= 1) 
  	            return false; 
  	        if (n <= 3) 
  	            return true; 
  	        if (n % 2 == 0 || n % 3 == 0) 
  	            return false; 
  	        double sq=Math.sqrt(n);
  	  
  	        for (int i = 5; i <= sq; i = i + 6) 
  	            if (n % i == 0 || n % (i + 2) == 0) 
  	                return false; 
  	        return true; 
  	    } 
          //pair class
          private static class Pair implements Comparable<Pair> {
              int first, second;
              public Pair(int f, int s) {
                  first = f;
                  second = s;
              }
              @Override
              public int compareTo(Pair p) {
                  if (first > p.first)
                      return 1;
                  else if (first < p.first)
                      return -1;
                  else {
                      if (second > p.second)
                          return 1;
                      else if (second < p.second)
                          return -1;
                      else
                          return 0;
                  }
              }
       
          }
  }