import sys
from collections import deque, defaultdict,Counter
from copy import deepcopy
from bisect import bisect_left, bisect_right, insort_left, insort_right
from heapq import heapify, heappop, heappush
from itertools import product, permutations, combinations, combinations_with_replacement
from functools import reduce
from math import gcd, sin, cos, tan, asin, acos, atan, degrees, radians, ceil, floor, log, sqrt, ceil, floor, pi, hypot
from string import ascii_lowercase
from decimal import Decimal, ROUND_HALF_UP, ROUND_HALF_EVEN
sys.setrecursionlimit(1000000)
INF = 10**18
MOD = 10**9+7
# MOD = 998244353
yes="Yes"
no="No"
from random import randint
def II():return int(input())
def SI():return str(input())
def MI():return map(int,input().split())
def MS():return map(str,input().split())
def LI():return list(map(int,input().split()))
n=II()
a=LI()
ans=a[0]+a[-1]
for i in range(1,n-1):
    ans+=(n-1)*a[i]
print(ans%MOD)