def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))

def main():
    N=I()
    A=LI()
    
    def sum2(x):
        return (x*(x+1))//2
    
    def calc(k):#k番目
        temp=sum2(k-1)*2
        temp+=k*(N-(k-1)*2)
        return temp
    
    ans=0
    B=[0]*N
    for i in range(N):
        d=calc(min(i+1,N-i))
        B[i]=A[i]*d
        
    print(sum(B))
        


main()