#include <bits/stdc++.h>
    using namespace std;
    #include <atcoder/all>
    using namespace atcoder;
    #define rep(i, n) for(int i=0;i<(n);++i)
    #define rep1(i, n) for(int i=1;i<=(n);i++)
    #define ll long long
    using mint = modint998244353;
    using P = pair<ll,ll>;
    using lb = long double;
    using T = tuple<ll, ll, ll>;
    #ifdef LOCAL
    #  include <debug_print.hpp>
    #  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
    #else
    #  define dbg(...) (static_cast<void>(0))
    #endif

    int main()
    {
        int n;
        cin >> n;
        vector<int> a(n);
        rep(i,n) cin >> a[i];
        mint ans = 0;
        if(n==1){
            cout << a[0] << endl;
            return 0;
        }
        else if(n==2){
            mint ans = 3*a[1] + 2*a[0];
            cout << ans.val() << endl;
            return 0;
        }
        rep1(i,n-1){
            ans += mint(2).pow(n-3) * (i+1) * a[i-1];
            dbg(ans.val());
        }
        ans += mint(2).pow(n-2) * (n+1) * a[n-1];
        cout << ans.val() << endl;
        return 0;
    }