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.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.StringTokenizer;
  
  public class Solve {
  
  	static long MOD = 998244353L;
  	static long INF = 1000_000_000_000_000L + 100;
  	static boolean isPrime[];
  
  	public static void main(String[] args) throws Exception {
  		Scanner sc = new Scanner();
  		PrintWriter pw = new PrintWriter(System.out);
  
  		int t = sc.nextInt();
  		while (t-- > 0) {
  			int n = sc.nextInt();
  			int a[] = sc.nextIntArray(n);
  			long c0 = 0;
  			long c1 = 0;
  			for (int i : a) {
  				if (i == 0)
  					c0++;
  				if (i == 1)
  					c1++;
  			}
  			long ans = 0;
  			if (c1 > 0)
  				ans = c1;
  			if (c0 > 0)
  				ans = (long) (ans * Math.pow(2, c0));
  			pw.println(ans);
  
  		}
  		pw.flush();
  
  	}
  
  	static int LowerBound(int a[], int x, int start) { // x is the target value or key
  		int ans = -1;
  
  		int l = start, r = a.length;
  		while (l + 1 < r) {
  			System.out.println("lolk");
  
  			int m = (l + r) >>> 1;
  			if (a[m] >= x) {
  				ans = m;
  				r = m;
  			} else
  				l = m;
  		}
  		return ans;
  	}
  
  	static int UpperBound(int a[], int x, int start) {// x is the key or target value
  		int ans = -1;
  
  		int l = start, r = a.length;
  		while (l + 1 < r) {
  			int m = (l + r) >>> 1;
  			if (a[m] <= x) {
  				ans = m;
  				l = m;
  			} else
  				r = m;
  		}
  		return ans;
  	}
  
  	static public boolean[] sieve(int n) {
  		boolean prime[] = new boolean[n + 1];
  		for (int i = 0; i <= n; i++)
  			prime[i] = true;
  
  		for (int p = 2; p * p <= n; p++) {
  			// If prime[p] is not changed, then it is a
  			// prime
  			if (prime[p] == true) {
  				// Update all multiples of p
  				for (int i = p * p; i <= n; i += p)
  					prime[i] = false;
  			}
  		}
  		return prime;
  
  	}
  
  	public static ArrayList<Integer> primeFactors(int n) {
  		ArrayList<Integer> set = new ArrayList<Integer>();
  
  		// Print the number of 2s that divide n
  		while (n % 2 == 0) {
  			n /= 2;
  			set.add(2);
  		}
  
  		// n must be odd at this point. So we can
  		// skip one element (Note i = i +2)
  		for (int i = 3; i * i <= n; i += 2) {
  			// While i divides n, print i and divide n
  			while (n % i == 0) {
  				n /= i;
  				set.add(i);
  			}
  		}
  
  		if (n > 1)
  			set.add(n);
  
  		return set;
  
  	}
  
  	static int gcd(int a, int b) {
  		if (a == 0)
  			return b;
  		if (b == 0)
  			return a;
  
  		return gcd(b, a % b);
  
  	}
  
  	public static int[] swap(int data[], int left, int right) {
  
  		// Swap the data
  		int temp = data[left];
  		data[left] = data[right];
  		data[right] = temp;
  
  		// Return the updated array
  		return data;
  	}
  
  	public static long[] euclidExtended(long a, long b) {
  		if (b == 0) {
  			long ar[] = new long[] { 1, 0 };
  			return ar;
  		}
  		long ar[] = euclidExtended(b, a % b);
  		long temp = ar[0];
  		ar[0] = ar[1];
  		ar[1] = temp - (a / b) * ar[1];
  		return ar;
  	}
  
  	public static long modInverse(long a, long m) {
  		long ar[] = euclidExtended(a, m);
  		return ((ar[0] % m) + m) % m;
  	}
  
  	// Fermat Theorem
  	public static long ncr(int n, int r, long[] fact) {
  		if (n == r)
  			return 1;
  		if (r == 1)
  			return n;
  		if (n == 0 || r == 0)
  			return 1;
  		return (fact[n] * modInverse(((long) fact[n - r]) * fact[r], MOD)) % MOD;
  	}
  
  	static void sort(int[] a) {
  		ArrayList<Integer> l = new ArrayList<>();
  		for (int i : a)
  			l.add(i);
  		Collections.sort(l);
  		for (int i = 0; i < a.length; i++)
  			a[i] = l.get(i);
  	}
  
  }
  
  class Pair {
  	int x, y;
  
  	Pair(int x, int y) {
  		this.x = x;
  		this.y = y;
  	}
  
  }
  
  class SegTree {
  	int leftmost, rightmost, sum;
  	SegTree lChild, rChild;
  
  	public SegTree(int leftmost, int rightmost) {
  		this.leftmost = leftmost;
  		this.rightmost = rightmost;
  	}
  
  	public void update(int index, int val) {
  		sum++;
  		if (leftmost == rightmost) {
  			return;
  		}
  		if (lChild == null)
  			makeKids();
  		if (index <= lChild.rightmost)
  			lChild.update(index, val);
  		else
  			rChild.update(index, val);
  	}
  
  	public void makeKids() {
  		int mid = (leftmost + rightmost) / 2;
  		lChild = new SegTree(leftmost, mid);
  		rChild = new SegTree(mid + 1, rightmost);
  	}
  
  	public int query(int l, int r) {
  		if (l <= leftmost && r >= rightmost)
  			return sum;
  		if (l > rightmost || r < leftmost)
  			return 0;
  		if (lChild == null)
  			return 0;
  		return lChild.query(l, r) + rChild.query(l, r);
  	}
  }
  
  class UnionFind {
  	int[] p, rank, setSize;
  	int numSets;
  
  	public UnionFind(int N) {
  		p = new int[numSets = N];
  		rank = new int[N];
  		setSize = new int[N];
  		for (int i = 0; i < N; i++) {
  			p[i] = i;
  			setSize[i] = 1;
  		}
  	}
  
  	public int findSet(int i) {
  		return p[i] == i ? i : (p[i] = findSet(p[i]));
  	}
  
  	public boolean isSameSet(int i, int j) {
  		return findSet(i) == findSet(j);
  	}
  
  	public void unionSet(int i, int j) {
  		if (isSameSet(i, j))
  			return;
  		numSets--;
  		int x = findSet(i), y = findSet(j);
  		if (rank[x] > rank[y]) {
  			p[y] = x;
  			setSize[x] += setSize[y];
  		} else {
  			p[x] = y;
  			setSize[y] += setSize[x];
  			if (rank[x] == rank[y])
  				rank[y]++;
  		}
  	}
  
  	public int numDisjointSets() {
  		return numSets;
  	}
  
  	public int sizeOfSet(int i) {
  		return setSize[findSet(i)];
  	}
  }
  
  class Scanner {
  	BufferedReader br;
  	StringTokenizer st;
  
  	Scanner() {
  		br = new BufferedReader(new InputStreamReader(System.in));
  	}
  
  	String next() throws IOException {
  		while (st == null || !st.hasMoreElements())
  			st = new StringTokenizer(br.readLine());
  		return st.nextToken();
  	}
  
  	int nextInt() throws NumberFormatException, IOException {
  		return Integer.parseInt(next());
  	}
  
  	int[] nextIntArray(int n) throws NumberFormatException, IOException {
  		int a[] = new int[n];
  		for (int i = 0; i < n; i++)
  			a[i] = Integer.parseInt(next());
  		return a;
  	}
  
  	long nextLong() throws NumberFormatException, IOException {
  		return Long.parseLong(next());
  	}
  
  	long[] nextLongArray(int n) throws NumberFormatException, IOException {
  		long a[] = new long[n];
  		for (int i = 0; i < n; i++)
  			a[i] = Long.parseLong(next());
  		return a;
  	}
  
  	double nextDouble() throws NumberFormatException, IOException {
  		return Double.parseDouble(next());
  	}
  }