#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define all(x) (x).begin(),(x).end() #define rep(i,m,n) for(int i = m;i < n;++i) #define pb push_back #define fore(i,a) for(auto &i:a) #define rrep(i,m,n) for(int i = m;i >= n;--i) #define INF INT_MAX/2 using namespace std; using ll = long long; using R = double; using Data = pair>; const ll MOD = 1e9 + 7; const ll inf = 1LL << 50; struct edge { ll from; ll to; ll cost; }; const int MAX = 101010; ll fac[MAX], finv[MAX], inv[MAX]; void combinit() { fac[0] = fac[1] = 1; finv[0] = finv[1] = 1; inv[1] = 1; for (int i = 2; i < MAX; i++) { fac[i] = fac[i - 1] * i % MOD; inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD; finv[i] = finv[i - 1] * inv[i] % MOD; } } ll comb(int n, int k) { if (n < k) return 0; if (n < 0 || k < 0) return 0; return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD; } int main() { combinit(); int n; cin >> n; vectora(n); rep(i, 0, n)cin >> a[i]; if (n == 1)cout << a[0] << endl; else if (n == 2)cout << a[0] + a[1] << endl; else { ll ans = 0; rep(i, 0, n) { ans += comb(n-1,i)*a[i]; ans %= MOD; } cout << ans << endl; } return 0; }