#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <functional>
#include <bitset>
#include <cstddef>
#include <type_traits>
#include <vector>

using namespace std;
using lint = long long int;
long long int INF = 1001001001001001LL;
int inf = 1000000007;
long long int MOD = 998244353;
double PI = 3.1415926535897932;

template<typename T1,typename T2>inline void chmin(T1 &a,const T2 &b){if(a>b) a=b;}
template<typename T1,typename T2>inline void chmax(T1 &a,const T2 &b){if(a<b) a=b;}

#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define rep(i, n) for(int i=0;i<(int)(n);i++)


int main() {
  
  lint n; cin >> n;
  vector<lint> modPow2(n);
  modPow2[0] = 1;
  for (int i = 1; i < n; i++) {
    modPow2[i] = modPow2[i - 1] * 2 % MOD;
  }

  lint ans = 0;
  for (int i = 1; i <= n; i++) {
    lint a; cin >> a;
    if (i == 1) {
      ans += modPow2[i - 1] * a % MOD * modPow2[n - i];
    } else {
      ans += (modPow2[i - 1] + (i - 1) * modPow2[i - 2]) % MOD * a % MOD * modPow2[n - i];
    }
    ans %= MOD;
  }

  cout << ans << endl;
  return 0;
}