#ifdef LOCAL
#include <local.hpp>
#else
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2")
#include <bits/stdc++.h>
#define debug(...) ((void)0)
#define postprocess(...) ((void)0)
#endif

#include <atcoder/modint.hpp>
using mint = atcoder::modint998244353;
namespace atcoder {
template <int m, std::enable_if_t<(1 <= m)>* = nullptr>
std::ostream& operator<<(std::ostream& os, const static_modint<m>& x) {
    return os << x.val();
}
}  // namespace atcoder

using namespace std;
using ll = long long;
using ld = long double;

mint make_factor(int n) {
    if (n == 0) return 1;
    return mint(2).pow(n - 1) * mint(n + 2);
}

void solve([[maybe_unused]] int test) {
    int N;
    cin >> N;

    mint ans = 0;

    for (int i = 0; i < N; i++) {
        int x;
        cin >> x;

        ans += mint(x) * make_factor(i) * make_factor(N - i - 1);
    }

    cout << ans << endl;
}

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

    int t = 1;
    // cin >> t;
    for (int i = 1; i <= t; i++) {
        solve(i);
    }

    postprocess();
}