
    In a city's traffic management system that uses hexagonal grid patterns for signal coordination, determine the total number of synchronized traffic signals that need to be included when expanding from the central intersection to the nth layer of intersections. The number will help establish optimal signal timing patterns for coordinated traffic flow across the expanding network.
    

    
def hexagonal_num(n):
    """
    In a city's traffic management system that uses hexagonal grid patterns for signal coordination, determine the total number of synchronized traffic signals that need to be included when expanding from the central intersection to the nth layer of intersections. The number will help establish optimal signal timing patterns for coordinated traffic flow across the expanding network.
    

    """
def hexagonal_num(n):
    """
    In a city's traffic management system that uses hexagonal grid patterns for signal coordination, determine the total number of synchronized traffic signals that need to be included when expanding from the central intersection to the nth layer of intersections. The number will help establish optimal signal timing patterns for coordinated traffic flow across the expanding network.
    

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