#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstring>
#include <cstdlib>
#include <cmath>
using namespace std;
using ll = long long;

constexpr int P = 998244353;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;

    ll r, t = 1;
    cin >> r;
    r %= P;

    for (int i = 1; i < n; i++) {
        int a;
        cin >> a;

        r *= 2;
        r += ((i + 2) * t) % P * a;
        r %= P;

        t *= 2;
        if (t >= P) t -= P;
    }

    cout << r << endl;

    return 0;
}