#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const ll mod=1000000007;
const ll inv2=(mod+1)/2;
inline ll ksm(ll a,ll x){
	ll ret=1;
	for (;x;x>>=1,a=a*a%mod) if (x&1) ret=ret*a%mod;
	return ret;
}
inline ll inv(ll a){return ksm(a,mod-2);}
void add(ll &A,ll B){A+=B;if (A>=mod) A-=mod;}
void sub(ll &A,ll B){A-=B;if (A<0) A+=mod;}

const int maxn=2000;
ll fac[maxn+50];
ll ifac[maxn+50];
void prepare(){
	fac[0]=1;
	for (int i=1;i<=maxn;i++) fac[i]=fac[i-1]*i%mod;
	ifac[maxn]=inv(fac[maxn]);
	for (int i=maxn-1;i>=0;i--) ifac[i]=ifac[i+1]*(i+1)%mod;
//	for (int i=0;i<=5;i++) cout << fac[i] << " ";
//	cout << endl;
//	for (int i=0;i<=5;i++) cout << ifac[i] << " ";
//	cout << endl;	
}
ll C(ll n,ll m){
	if (m<0 || m>n) return 0;
	return fac[n]*ifac[m]%mod*ifac[n-m]%mod;	
}

ll n;
ll a[maxn+50];
ll cnt[55];
ll sum[55];
ll dp[55][maxn+50];

int main(){
	ios_base::sync_with_stdio(false);
	prepare();
	cin >> n;
	for (int i=1;i<=n;i++){
		cin >> a[i];
		for (int j=0;j<a[i];j++) cnt[j]++;	
	}
	for (int i=50;i>=0;i--) sum[i]=sum[i+1]+cnt[i];
	for (int i=1;i<=n;i++){
		for (int j=0;j<=i;j++){
			ll res=ksm(i-j,n)*C(n,j)%mod*ifac[n]%mod;
			if (j%2==0) add(dp[0][i-1],res);
			else sub(dp[0][i-1],res);
		}
	}
	for (int i=n-1;i>=1;i--) sub(dp[0][i],dp[0][i-1]);
	
	int lim=n-1;
	for (int i=0;i<=50;i++){
		ll invr=ksm(inv2,cnt[i]);
		int mx=0;
		for (int j=0;j<=lim;j++){
			for (int l=0;l<=cnt[i];l++){
				ll coef=C(cnt[i],l)*invr%mod;
				int index=(j+l)/2;
				mx=max(mx,index);
				add(dp[i+1][index],dp[i][j]*coef%mod);
			}
		}
		lim=mx;
	}
	ll ans=0;
	for (int i=1;i<=n;i++){
		add(ans,dp[a[i]][0]*ksm(inv2,sum[a[i]])%mod);
	}
	ans=(mod+1-ans)%mod;
	cout << ans << "\n";
	return 0;
}