#include <bits/stdc++.h>
using namespace std;
#if __has_include("Today's/debug.cpp")
#include "Today's/debug.cpp"
#else
#define debug(...)
#define print_line
#define debugc(...)
#define cerr \
	if (false) cerr
#endif
#include <atcoder/modint>
using namespace atcoder;

int main() {
	int N;
	cin >> N;
	vector<int> A(N + 1);
	for (int i = 1; i <= N; i++) {
		cin >> A[i];
	}
	modint998244353 ans = 0;
	for (int i = 1; i <= N; i++) {
		modint998244353 num = i == 1 ? 1 : (i + 1) * modint998244353::raw(2).pow(i - 2);
		ans += num * A[i] * modint998244353::raw(2).pow(max(0, N - i - 1));
	}
	cout << ans.val() << endl;
}