#include using namespace std; using int64 = long long; const int mod = 1e9 + 7; const int inf = (1 << 30) - 1; const int64 infll = (1LL << 61) - 1; struct IoSetup { IoSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(10); cerr << fixed << setprecision(10); } } iosetup; template< typename T > ostream &operator<<(ostream &os, const vector< T > &v) { for(int i = 0; i < (int) v.size(); i++) { os << v[i] << (i + 1 != v.size() ? " " : ""); } return os; } template< typename T > istream &operator>>(istream &is, vector< T > &v) { for(T &in : v) is >> in; return is; } template< typename T1, typename T2 > inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); } template< typename T1, typename T2 > inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); } template< typename T = int64 > vector< T > make_v(size_t a) { return vector< T >(a); } template< typename T, typename... Ts > auto make_v(size_t a, Ts... ts) { return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...)); } template< typename T, typename V > typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) { t = v; } template< typename T, typename V > typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) { for(auto &e : t) fill_v(e, v); } template< int mod > struct Combination { vector< int64_t > mfact, rfact; Combination(int sz) : mfact(sz + 1), rfact(sz + 1) { mfact[0] = 1; for(int i = 1; i < mfact.size(); i++) { mfact[i] = mfact[i - 1] * i % mod; } rfact[sz] = inv(mfact[sz]); for(int i = sz - 1; i >= 0; i--) { rfact[i] = rfact[i + 1] * (i + 1) % mod; } } int64_t fact(int k) const { return (mfact[k]); } int64_t pow(int64_t x, int64_t n) const { int64_t ret = 1; while(n > 0) { if(n & 1) (ret *= x) %= mod; (x *= x) %= mod; n >>= 1; } return (ret); } int64_t inv(int64_t x) const { return (pow(x, mod - 2)); } int64_t P(int n, int r) const { if(r < 0 || n < r) return (0); return (mfact[n] * rfact[n - r] % mod); } int64_t C(int p, int q) const { if(q < 0 || p < q) return (0); return (mfact[p] * rfact[q] % mod * rfact[p - q] % mod); } int64_t H(int n, int r) const { if(n < 0 || r < 0) return (0); return (r == 0 ? 1 : C(n + r - 1, r)); } }; int main() { int N; cin >> N; vector< int > A(N); cin >> A; Combination< mod > latte(N); int64 add = 0; for(int i = N - 1; i >= 0; i--) { add += 1LL * latte.C(N - 1, i) * A[i] % mod; add %= mod; } cout << add << endl; }