#include #define rep(i,n) for(int i=0;i<(int)(n);i++) using namespace std; using ll = long long ; using P = pair ; using pll = pair; constexpr int INF = 1e9; constexpr long long LINF = 1e17; constexpr int MOD = 1000000007; constexpr double PI = 3.14159265358979323846; const int MAX = 1000000; long long fac[MAX], finv[MAX], inv[MAX]; void COMinit() { 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; } } // 二項係数 long long COM(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(){ COMinit(); int n; cin >> n; vector a(n); rep(i,n) cin >> a[i]; ll ans = 0; rep(i,n){ ans += (a[i] * COM(n-1,i))%MOD; ans %= MOD; } cout << ans << endl; return 0; }