#include<bits/stdc++.h>
using namespace std;
using LL=long long;
using ULL=unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)

const ULL M=998244353;
const int Z=500000;

int N;
ULL A[Z];

int main(){
	cin>>N;
	rep(i,N) cin>>A[i];
	ULL a=0; rep(i,N) a+=(i+2)*A[i]%M; a%=M;
	rep(i,N-1) a=a*2%M;
	a=a*(M/2+1)%M;
	cout<<a<<endl;
	return 0;
}