#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const int mod = 1e9 + 7;
int norm(int x) { return x >= mod ? x - mod : x; }
int reduce(int x) { return x < 0 ? x + mod : x; }
int neg(int x) { return x ? mod - x : 0; }
int quo2(int x) { return (x + (x & 1 ? mod : 0)) >> 1; }
void add(int &x, int y) { x += y, x = x >= mod ? x - mod : x; }
void sub(int &x, int y) { x -= y, x = x < 0 ? x + mod : x; }
void fam(int &x, int y, int z) { x = (x + (ll)y * z) % mod; }
int mpow(int a, int b) {
  int ret = 1;
  for (; b; b >>= 1) {
    if (b & 1) ret = (ll)ret * a % mod;
    a = (ll)a * a % mod;
  }
  return ret;
}

const int N = 1e3;
const int V = 50;

int n;
int fac[N + 5], ifac[N + 5], pw[N + 5], g[N + 5];
int a[N + 5], inv = 1, cnt[N + 5];
int f[V + 5][N + 5];
int ans;

int main() {
  scanf("%d", &n), fac[0] = 1;
  for (int i = 1; i <= n; ++i) fac[i] = (ll)fac[i - 1] * i % mod;
  ifac[n] = mpow(fac[n], mod - 2);
  for (int i = n; i; --i) ifac[i - 1] = (ll)ifac[i] * i % mod;
  for (int i = 0; i <= n; ++i) pw[i] = mpow(i, n);
  for (int i = 1; i <= n; ++i)
    for (int j = 0; j <= i; ++j)
      g[i] = (g[i] + (ll)(j & 1 ? mod - ifac[j] : ifac[j]) * ifac[n - j] * pw[i - j]) % mod;
  for (int i = 1; i <= n; ++i) scanf("%d", a + i), ++cnt[a[i]], inv = (ll)inv * mpow(2, mod - 1 - a[i]) % mod;
  for (int i = V; i; --i) cnt[i - 1] += cnt[i];
  for (int i = 0; i < n; ++i) f[0][i] = reduce(g[i + 1] - g[i]);
  for (int i = 0; i < V; ++i)
    for (int j = 0; j <= n; ++j)
      if (f[i][j])
        for (int k = 0; k <= cnt[i + 1]; ++k)
          fam(f[i + 1][(j + k) >> 1], f[i][j], (ll)fac[cnt[i + 1]] * ifac[k] % mod * ifac[cnt[i + 1] - k] % mod);
  for (int i = 1; i <= n; ++i) add(ans, f[a[i]][0]);
  ans = (1 + (ll)(mod - ans) * inv) % mod, printf("%d\n", ans);
}