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

int main(){
  ll n;
  cin>>n;
  vector<ll> a(n);
  for(ll i=0;i<n;i++){
    cin>>a[i];
  }
  ll mod=998244353;
  vector<ll> pw(n);
  pw[0]=1;
  for(ll i=0;i<n-1;i++){
    pw[i+1]=pw[i]*2;
    pw[i+1]%=mod;
  }
  ll ans=0;
  for(ll i=0;i<n;i++){
    ll l=i;
    ll r=n-1-i;
    ll lc;
    if(l==0){
      lc=1;
    }else{
      lc=(l+2)*pw[l-1];
      lc%=mod;
    }
    ll rc;
    if(r==0){
      rc=1;
    }else{
      rc=(r+2)*pw[r-1];
      rc%=mod;
    }
    ans+=(((a[i]*lc)%mod)*rc)%mod;
    ans%=mod;
  }
  cout<<ans<<endl;
}