
    As part of an adaptive geometry pattern recognition module, develop a function that calculates the nth octagonal pattern size based on a student's current progression level. The function should determine the total number of points needed to form a complete octagonal shape at the specified progression level, helping students visualize and understand geometric growth patterns.
    

    
def is_octagonal(n):
    """
    As part of an adaptive geometry pattern recognition module, develop a function that calculates the nth octagonal pattern size based on a student's current progression level. The function should determine the total number of points needed to form a complete octagonal shape at the specified progression level, helping students visualize and understand geometric growth patterns.
    

    """
def is_octagonal(n):
    """
    As part of an adaptive geometry pattern recognition module, develop a function that calculates the nth octagonal pattern size based on a student's current progression level. The function should determine the total number of points needed to form a complete octagonal shape at the specified progression level, helping students visualize and understand geometric growth patterns.
    

    """
    return 3 * n * n - 2 * n