#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

int N;
ll A[202020];

int main() {
  cin >> N;
  for (int i = 1; i <= N; i++) cin >> A[i];
  mint ans = 0;
  for (int i = 1; i <= N; i++) {
    ans += A[i] * mint(2).pow(max(0, N - i - 1)) * ((i - 1) * mint(2).pow(max(0, i - 2)) + mint(2).pow(i - 1));
  }
  cout << ans.val() << endl;
  return 0;
}