#include using namespace std; #define ll long long #define rep(i, n) for (ll i = 0; i < n; ++i) #define P pair #define Graph vector> #define fi first #define se second #define vvvvll vector>>> #define vvvll vector>> #define vvll vector> #define vll vector #define pqll priority_queue #define pqllg priority_queue, greater> constexpr ll INF = (1ll << 60); // constexpr ll mod = 998244353; constexpr ll mod = 1000000007; // constexpr ll mod = 67280421310721; constexpr double pi = 3.14159265358979323846; template inline bool chmax(T &a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T &a, T b) { if (a > b) { a = b; return 1; } return 0; } void pt_vvll(vvll v) { ll vs = v.size(), vs0 = v[0].size(); rep(i, vs) { rep(j, vs0) { cout << v[i][j]; if (j != vs0 - 1) cout << " "; else cout << "\n"; } } } void pt_vll(vll v) { ll vs = v.size(); rep(i, vs) { cout << v[i]; if (i == vs - 1) cout << "\n"; else cout << " "; } } #define MAX 1000100 ll 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 (ll 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 ll combi(ll n, ll 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() { ios::sync_with_stdio(false); cin.tie(nullptr); COMinit(); ll N; cin >> N; vll a(N); rep(i, N) cin >> a[i]; ll ans = 0; rep(i, N) { ans += (combi(N - 1, i) * a[i]) % mod; ans %= mod; } cout << ans << "\n"; return 0; }