#include #define rep(i,n) for(int i = 0; i < (n); ++i) #define srep(i,s,t) for (int i = s; i < t; ++i) #define drep(i,n) for(int i = (n)-1; i >= 0; --i) using namespace std; typedef long long int ll; typedef pair P; #define yn {puts("Yes");}else{puts("No");} #define MAX_N 200005 const int MAX = 510000; const int MOD = 1000000007; long long fac[MAX], finv[MAX], inv[MAX]; // テーブルを作る前処理 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; } } // 二項係数計算 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; } long long FINV(int n){ if (n < 0) return 0; return finv[n]; } int main() { COMinit(); int n; cin >> n; ll 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; }