import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
    
            //indexed backwards
    //eg. -infinity,...4,3,2,1 --ends at 1
    static double putThroughEquation(long index){
       
        return 6 * Math.pow(index, 2) - 16 * index + 11;//number of times number appears in final round
    }

    static int solve(int[] arr) {
        //  Return the sum of S(S(A)) modulo 10^9+7.
        long sum = 0;
        int length = arr.length;
        int[] appearances = new int[arr.length];
        
        for(int i = 0; i < appearances.length; i++){
            appearances[i] = (int) putThroughEquation(appearances.length - i);
        }
        
        for(int i = 0; i < arr.length; i++){
            sum += arr[i] * appearances[i];
            
        }
        int temp = (int) (sum % (Math.pow(10,9) + 7));
        return temp;
        
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] a = new int[n];
        for(int a_i = 0; a_i < n; a_i++){
            a[a_i] = in.nextInt();
        }
        
        int result = solve(a);
        System.out.println(result);
        in.close();
        
    }
}