#define _CRT_SECURE_NO_WARNINGS

#include <bits/stdc++.h>
using namespace std;

#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;


int main() {
//	input_from_file("input.txt");
//	output_to_file("output.txt");

	int n;
	cin >> n;

	vector<int> a(n);
	for (int i = 0; i < n; i++) cin >> a[i];

	vector<mint> pow2(n);
	pow2[0] = 1;
	for (int i = 1; i < n; i++) pow2[i] = pow2[i - 1] * 2;

	mint res;
	for (int i = 0; i < n; i++) {
		int l = i;
		int r = n - 1 - i;
		mint lc = (l == 0 ? 1 : (l + 2) * pow2[l - 1]);
		mint rc = (r == 0 ? 1 : (r + 2) * pow2[r - 1]);
		res += a[i] * lc * rc;
	}

	cout << res.val() << endl;
}