## https://yukicoder.me/problems/no/2938

def main():
    N = int(input())
    A = list(map(int, input().split()))

    answer = 0
    for i in range(N):
        for j in range(N):
            s = abs(i - j) * abs(A[i] - A[j])
            answer += s
    print(answer)















if __name__ == "__main__":
    main()