#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int n, c[1000],m,sum=0;
    cin>>n;
    for(int i=0; i<n;i++){
        cin>>c[i];
        m=(2^(i))+c[i];
        sum+=m;
    }
    cout<<sum;
    return 0;
}