#include <iostream>
#include <algorithm>

typedef long long ll;
typedef double lf;

// #define DEBUG 1
struct IO
{
    #define MAXSIZE (1 << 20)
    #define isdigit(x) (x >= '0' && x <= '9')
    char buf[MAXSIZE], *p1, *p2;
    char pbuf[MAXSIZE], *pp;
    #if DEBUG
    #else
    IO() : p1(buf), p2(buf), pp(pbuf) {}
    ~IO() {fwrite(pbuf, 1, pp - pbuf, stdout);}
    #endif
    #define gc() (p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, MAXSIZE, stdin), p1 == p2) ? ' ' : *p1++)
    #define blank(x) (x == ' ' || x == '\n' || x == '\r' || x == '\t')

    template <typename T>
    void Read(T &x)
    {
        #if DEBUG
        std::cin >> x;
        #else
        bool sign = 0; char ch = gc(); x = 0;
        for (; !isdigit(ch); ch = gc())
            if (ch == '-') sign = 1;
        for (; isdigit(ch); ch = gc()) x = x * 10 + (ch ^ 48);
        if (sign) x = -x;
        #endif
    }
    void Read(char *s)
    {
        #if DEBUG
        std::cin >> s;
        #else
        char ch = gc();
        for (; blank(ch); ch = gc());
        for (; !blank(ch); ch = gc()) *s++ = ch;
        *s = 0;
        #endif
    }
    void Read(char &c) {for (c = gc(); blank(c); c = gc());}

    void Push(const char &c)
    {
        #if DEBUG
        putchar(c);
        #else
        if (pp - pbuf == MAXSIZE) fwrite(pbuf, 1, MAXSIZE, stdout), pp = pbuf;
        *pp++ = c;
        #endif
    }
    template <typename T>
    void Write(T x)
    {
        if (x < 0) x = -x, Push('-');
        static T sta[35];
        int top = 0;
        do sta[top++] = x % 10, x /= 10; while (x);
        while (top) Push(sta[--top] ^ 48);
    }
    template <typename T>
    void Write(T x, char lst) {Write(x), Push(lst);}
} IO;
#define Read(x) IO.Read(x)
#define Write(x, y) IO.Write(x, y)
#define Put(x) IO.Push(x)

using namespace std;

const int MAXN = 1010, mod = 1e9 + 7;

ll fac[MAXN], inv[MAXN];
inline ll C(int n, int m) {return n < m ? 0 : fac[n] * inv[m] % mod * inv[n - m] % mod;}
inline ll Qpow(ll x, int y) {ll res = 1; while (y) (y & 1) && (res = res * x % mod), x = x * x % mod, y >>= 1; return res;}

int n, a[MAXN], c[60];
ll g[MAXN], f[60][MAXN << 1];

inline ll Calc(int x) {return Qpow(x, n) * inv[n] % mod;}

int main()
{
    #if DEBUG
    #else
    ios::sync_with_stdio(0), cin.tie(0);
    #endif

    fac[0] = fac[1] = inv[0] = inv[1] = 1;
    for (int i = 2; i < MAXN; i++) fac[i] = fac[i - 1] * i % mod, inv[i] = (mod - mod / i) * inv[mod % i] % mod;
    for (int i = 2; i < MAXN; i++) inv[i] = inv[i - 1] * inv[i] % mod;

    Read(n);
    for (int i = 1; i <= n; i++) Read(a[i]), c[a[i]]++;

    for (int i = 0; i <= n; i++)
        for (int j = 0; j <= i; j++)
            g[i] = (g[i] + (j & 1 ? -1 : 1) * C(n, j) * Calc(i - j)) % mod;
    g[n + 1] = 1;
    for (int i = 0; i <= n; i++) f[0][i] = (g[i + 1] - g[i] + mod) % mod;
    for (int i = 49; i >= 0; i--) c[i] += c[i + 1];
    for (int i = 0; i <= 50; i++)
    {
        for (int j = 0; j <= n; j++)
            if (f[i][j])
            {
                for (int k = 0; k <= c[i + 1]; k++)
                    f[i + 1][j + k >> 1] = (f[i + 1][j + k >> 1] + f[i][j] * C(c[i + 1], k)) % mod;
            }
    }
    ll ans = 0, sum = 0;
    for (int i = 1; i <= n; i++) ans = (ans + f[a[i]][0]) % mod, sum += a[i];
    ans = (1 - ans * Qpow(inv[2], sum) % mod + mod) % mod;
    cout << ans << '\n';
    return 0;
}