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


int main() {

    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll N,mod=998244353;;
    cin>>N;
    vector<ll> A(N),P(N+1,1);
    for(int i=0;i<N;i++){
        cin>>A[i];
        P[i+1]=(P[i]*2)%mod;
    }
    ll an=0;
    for(int i=0;i<N;i++){
        ll res=A[i]*(i*P[i-1]%mod+P[i]);
        res%=mod;
        if(i<N-1)res=(res*P[N-i-2])%mod;
        an+=res;
    }
    cout<<an%mod<<endl;
}