def cal_abs(n, sigma_list):
    abs_val = 0
    for i in range(n):
        for j in range(n):
            abs_val += abs(i - j) * abs(sigma_list[i] - sigma_list[j])
    return abs_val


def main():
    n = int(input())
    sigma_list = list(map(int, input().split()))
    answer = cal_abs(n, sigma_list)
    print(answer)


if __name__ == "__main__":
    main()