
    In a hexagonal grid-based delivery zone system, calculate the total number of service areas that can be reached within n concentric layers from the central depot, where each layer forms a perfect hexagonal pattern around the previous one. The result will help determine the optimal coverage area for efficient route planning and resource allocation in the fleet management network.
    

    
def hexagonal_num(n):
    """
    In a hexagonal grid-based delivery zone system, calculate the total number of service areas that can be reached within n concentric layers from the central depot, where each layer forms a perfect hexagonal pattern around the previous one. The result will help determine the optimal coverage area for efficient route planning and resource allocation in the fleet management network.
    

    """
def hexagonal_num(n):
    """
    In a hexagonal grid-based delivery zone system, calculate the total number of service areas that can be reached within n concentric layers from the central depot, where each layer forms a perfect hexagonal pattern around the previous one. The result will help determine the optimal coverage area for efficient route planning and resource allocation in the fleet management network.
    

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