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

const unsigned MOD = 1000000007;
struct mint
{
    unsigned v;
    mint(unsigned v_ = 0) : v(v_) {}
    mint &operator+=(const mint &X) { return (v += X.v) >= MOD ? v -= MOD : v, *this; }
    mint &operator-=(const mint &X) { return (v += MOD - X.v) >= MOD ? v -= MOD : v, *this; }
    mint &operator*=(const mint &X) { return v = 1llu * v * X.v % MOD, *this; }
    mint inv() const { return pow(MOD - 2); }
    mint &operator/=(const mint &X) { return *this *= X.inv(); }
    mint pow(long long B) const
    {
        mint res = 1, A = *this;
        while (B)
        {
            if (B & 1)
                res *= A;
            A *= A;
            B >>= 1;
        }
        return res;
    }
    friend mint operator+(const mint &A, const mint &B) { return mint(A) += B; }
    friend mint operator-(const mint &A, const mint &B) { return mint(A) -= B; }
    friend mint operator*(const mint &A, const mint &B) { return mint(A) *= B; }
    friend mint operator/(const mint &A, const mint &B) { return mint(A) /= B; }
    friend bool operator<(const mint &A, const mint &B) { return A.v < B.v; }
    friend bool operator==(const mint &A, const mint &B) { return A.v == B.v; }
    friend std::ostream &operator<<(std::ostream &A, const mint &B) { return A << B.v; }
};

const int N = 1005;
const mint inv2 = (MOD + 1) / 2;

int n, a[N], cnt[55], sum[55];
mint f[N], g[N], ans, fac[N], ifac[N], ipw[N], pwr[N];

void init(int n) {
    fac[0] = 1;
    for (int i = 1; i <= n; ++i) fac[i] = fac[i - 1] * i;
    ifac[n] = fac[n].inv();
    for (int i = n; i; --i) ifac[i - 1] = ifac[i] * i;
    ipw[0] = 1;
    for (int i = 1; i <= n; ++i) ipw[i] = ipw[i - 1] * inv2;
    for (int i = 0; i <= n; ++i) pwr[i] = mint(i).pow(::n);
}
mint C(int n, int m) {
    if (n < 0 || m < 0 || n < m) return 0;
    return fac[n] * ifac[m] * ifac[n - m];
}

mint P(int n, int t) { // sum <= t
    if (t >= n - 1) return 1;
    mint res = 0;
    for (int i = 0; i <= t; ++i) {
        mint val = C(n - 1, i) * (pwr[t - i + 1] - pwr[t - i]);
        if ((i & 1)) res -= val;
        else res += val;
    }
    return res * ifac[n];
}

int main() {
    ios::sync_with_stdio(0), cin.tie(0);

    cin >> n;
    init(N - 1);
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
        ++cnt[a[i]];
    }

    int tot = 0;
    mint coef = 1;

    for (int o = 49; o >= 0; --o) {
        memset(g, 0, sizeof g);
        tot += cnt[o + 1];
        coef *= ipw[tot];
        for (int i = 0; i <= n; ++i) f[i] *= ipw[tot];
        {
            for (int i = 0; i <= n; ++i) {
                mint cur = f[i];
                if (cur == 0) continue;
                for (int x = 0; x < 2; ++x) {
                    for (int y = 0; y <= tot - 1; ++y) {
                        int j = i * 2 + x - y;
                        if (j < 0) continue;
                        mint val = cur * C(tot - 1, y);
                        if (j > n) {
                            ans += val;
                        } else {
                            g[j] += val;
                        }
                    }
                }
            }
        } // max known, 1 verses tot-1 others
        {
            g[1] += coef * tot;
        } // max: 1
        {
            g[0] += coef * tot * (tot - 1);
        } // max: 2
        memcpy(f, g, sizeof f);
    }
    f[0] += coef * n;

    for (int t = 0; t <= n; ++t) {
        // cerr << "? " << t << " " << f[t] * coef.inv() << endl; 
        ans += f[t] * P(n, t);
    }
    // cout << ans * 120 << "\n";

    cout << 1 - ans << "\n";

    return 0;
}