
    Write a function to validate bank account numbers by determining if the account identifier is one less than twice its reverse, which serves as a security check pattern in the bank's fraud detection system. The function should process numerical account identifiers and help flag potentially suspicious accounts that match this specific numerical relationship pattern.
    

    
def rev(num):
    rev_num = 0
    while num > 0:
        rev_num = rev_num * 10 + num % 10
        num = num // 10
    return rev_num

def check(n):
    """
    Write a function to validate bank account numbers by determining if the account identifier is one less than twice its reverse, which serves as a security check pattern in the bank's fraud detection system. The function should process numerical account identifiers and help flag potentially suspicious accounts that match this specific numerical relationship pattern.
    

    """
def rev(num):
    rev_num = 0
    while num > 0:
        rev_num = rev_num * 10 + num % 10
        num = num // 10
    return rev_num

def check(n):
    """
    Write a function to validate bank account numbers by determining if the account identifier is one less than twice its reverse, which serves as a security check pattern in the bank's fraud detection system. The function should process numerical account identifiers and help flag potentially suspicious accounts that match this specific numerical relationship pattern.
    

    """
    return 2 * rev(n) == n + 1