#include <iostream>
#include <limits>
#include <array>

#define FOR(i, s, n) for(auto i = (s); i < n; ++i)
#define REP(i, n) FOR(i, decltype(n)(), n)

using ll = long long;
constexpr ll mod = 1000000007;

template <class T, T b>
class pow_preproc {
  using array_t = std::array<T, std::numeric_limits<T>::digits>;
  static constexpr array_t get_dp() {
    array_t dp = {b % mod};
    FOR(i, 1, std::numeric_limits<T>::digits) {
      dp[i] = (dp[i - 1] * dp[i - 1]) % mod;
    }
    return dp;
  }
  static constexpr array_t _dp = get_dp();
public:
  static constexpr T get_pow(T x) {
    if(x < 0) return 0;
    T y = 1;
    for(int i = 0; x; ++i) {
      if(x % 2) {
        y *= _dp[i];
        y %= mod;
      }
      x /= 2;
    }
    return y;
  }
};

std::array<int, 200001> a = {};
using pow3 = pow_preproc<ll, 3>;

int main() {
  int n;
  ll sum = 0;
  ll muls = 1;
  std::cin >> n;
  REP(i, n) {
    ll a;
    std::cin >> a;
    muls *= a; muls %= mod;
    ll p = pow3::get_pow(n - i - 2);
    if(p <= 0) p = 1;
    else {
      p *= 2;
      p %= mod;
    }
    sum += muls * p; if(sum > mod) sum -= mod;
  }
  std::cout << sum << '\n';
}