
    In a growing metropolitan transit system that uses hexagonal bus hub layouts for optimal coverage, determine the total number of possible route connections for the nth hub expansion zone. Each new hub zone follows a hexagonal pattern where the number of possible route connections grows according to the formula for hexagonal numbers, helping planners optimize the transit network's connectivity.
    

    
def hexagonal_num(n):
    """
    In a growing metropolitan transit system that uses hexagonal bus hub layouts for optimal coverage, determine the total number of possible route connections for the nth hub expansion zone. Each new hub zone follows a hexagonal pattern where the number of possible route connections grows according to the formula for hexagonal numbers, helping planners optimize the transit network's connectivity.
    

    """
def hexagonal_num(n):
    """
    In a growing metropolitan transit system that uses hexagonal bus hub layouts for optimal coverage, determine the total number of possible route connections for the nth hub expansion zone. Each new hub zone follows a hexagonal pattern where the number of possible route connections grows according to the formula for hexagonal numbers, helping planners optimize the transit network's connectivity.
    

    """
    return n * (2 * n - 1)