Find numbers that are divisible by 3 but not a multiple of 7

def divisible_numbers(numbers):
    """
    Returns a comma-separated sequence of numbers that are divisible by 3 but not a multiple of 7.

    Args:
    numbers (list): The list of numbers.

    Returns:
    str: The comma-separated sequence of numbers.
    """
    # TODO: Implement the divisible_numbers function
    pass