#include <bits/stdc++.h>

#define rep(i, j, k) for (int i = (j); i <= (k); ++i)
#define per(i, j, k) for (int i = (j); i >= (k); --i)
#define SZ(v) int((v).size())
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second
using ll = long long;
using pii = std::pair<int, int>;
using pll = std::pair<ll, ll>;

template<class T>inline void chkmn(T &x, T y) { if (y < x) x = y; }
template<class T>inline void chkmx(T &x, T y) { if (y > x) x = y; }

using namespace std;

template <int P>
class mod_int {
  using Z = mod_int;

private:
  static int mo(int x) { return x < 0 ? x + P : x; }

public:
  int x;
  int val() const { return x; }
  mod_int() : x(0) {}
  template <class T>
  mod_int(const T &x_) : x(x_ >= 0 && x_ < P ? static_cast<int>(x_) : mo(static_cast<int>(x_ % P))) {}
  bool operator==(const Z &rhs) const { return x == rhs.x; }
  bool operator!=(const Z &rhs) const { return x != rhs.x; }
  Z operator-() const { return Z(x ? P - x : 0); }
  Z pow(long long k) const {
    Z res = 1, t = *this;
    while (k) {
      if (k & 1) res *= t;
      if (k >>= 1) t *= t;
    }
    return res;
  }
  Z &operator++() {
    x < P - 1 ? ++x : x = 0;
    return *this;
  }
  Z &operator--() {
    x ? --x : x = P - 1;
    return *this;
  }
  Z operator++(int) {
    Z ret = x;
    x < P - 1 ? ++x : x = 0;
    return ret;
  }
  Z operator--(int) {
    Z ret = x;
    x ? --x : x = P - 1;
    return ret;
  }
  Z inv() const { return pow(P - 2); }
  Z &operator+=(const Z &rhs) {
    (x += rhs.x) >= P && (x -= P);
    return *this;
  }
  Z &operator-=(const Z &rhs) {
    (x -= rhs.x) < 0 && (x += P);
    return *this;
  }
  Z &operator*=(const Z &rhs) {
    x = 1ULL * x * rhs.x % P;
    return *this;
  }
  Z &operator/=(const Z &rhs) { return *this *= rhs.inv(); }
#define setO(T, o)                                 \
  friend T operator o(const Z &lhs, const Z &rhs) {\
    Z res = lhs;                                   \
    return res o## = rhs;                          \
  }
  setO(Z, +) setO(Z, -) setO(Z, *) setO(Z, /)
#undef setO
};
const int P = 1e9 + 7;
using Z = mod_int<P>;

const int maxn = 1000010;
const Z base = 133331;

using info = vector<int>;

Z fac[maxn], ivf[maxn], pw[maxn];
int n, m, tf, tg, a[maxn], cnt[maxn], p[maxn];
pair<info, pair<Z, Z>> f[maxn], g[maxn];

Z binom(int x, int y) {
  if (x < 0 || y < 0 || x < y) return 0;
  return fac[x] * ivf[y] * ivf[x - y];
}

int main() {
  fac[0] = 1;
  rep (i, 1, maxn - 1) fac[i] = fac[i - 1] * i;
  ivf[maxn - 1] = fac[maxn - 1].inv();
  per (i, maxn - 1, 1) ivf[i - 1] = ivf[i] * i;
  pw[0] = 1;
  rep (i, 1, maxn - 1) pw[i] = pw[i - 1] * base;
  cin.tie(nullptr) -> ios::sync_with_stdio(false);
  cin >> n;
  rep (i, 0, n) cin >> a[i], chkmx(m, a[i]);
  rep (i, 1, n) cnt[a[i]]++;
  if (a[0] == 0 && cnt[0] == n) return cout << fac[n].val() << '\n', 0;
  if (a[0] == 0) return cout << 0 << '\n', 0;
  if (a[0] == m) return cout << fac[n].val() << '\n', 0;
  vector<int> buc(m + 1, 0);
  Z res = 1;
  rep (i, 1, m) res *= ivf[cnt[i]];
  f[tf = 1] = make_pair(buc, make_pair(res, 0));
  Z coe = binom(n, cnt[0]) * fac[cnt[0]], ans = 0;
  rep (i, 1, m) coe *= fac[cnt[i]];
  while (tf) {
    tg = 0;
    rep (_, 1, tf) {
      buc = f[_].fi;
      int sum = a[0];
      rep (i, 1, m) sum += i * buc[i];
      int rest = n - cnt[0] - 1;
      rep (k, 1, m) rest -= buc[k];
      rep (i, 1, min(m, sum)) if (buc[i] < cnt[i]) {
        buc[i]++;
        if (sum + i >= m || rest == 0) {
          Z res = coe * f[_].se.fi * fac[rest] * (cnt[i] - buc[i] + 1);
          ans += res;
        } else {
          g[++tg] = make_pair(buc, make_pair(f[_].se.fi * (cnt[i] - buc[i] + 1), f[_].se.se + pw[i]));
          p[tg] = tg;
        }
        buc[i]--;
      }
    }
    sort(p + 1, p + tg + 1, [&](int x, int y) { return g[x].se.se.val() < g[y].se.se.val(); }), tf = 0;
    for (int l = 1, r; l <= tg; l = r + 1) {
      r = l;
      while (r < tg && g[p[l]].se.se == g[p[r + 1]].se.se) r++;
      Z sum = 0;
      rep (i, l, r) sum += g[p[i]].se.fi;
      f[++tf] = make_pair(g[p[l]].fi, make_pair(sum, g[p[l]].se.se));
    }
  }
  cout << ans.val() << '\n';
}