
    Design a function that determines the total number of potential fraud connection points at a given complexity level n in the bank's pattern analysis sequence, where each level follows a decagonal expansion pattern representing interconnected suspicious transactions. The number of connection points at each level must follow the formula for decagonal numbers to accurately map transaction relationship clusters in the fraud detection system.
    

    
def is_num_decagonal(n):
    """
    Design a function that determines the total number of potential fraud connection points at a given complexity level n in the bank's pattern analysis sequence, where each level follows a decagonal expansion pattern representing interconnected suspicious transactions. The number of connection points at each level must follow the formula for decagonal numbers to accurately map transaction relationship clusters in the fraud detection system.
    

    """
def is_num_decagonal(n):
    """
    Design a function that determines the total number of potential fraud connection points at a given complexity level n in the bank's pattern analysis sequence, where each level follows a decagonal expansion pattern representing interconnected suspicious transactions. The number of connection points at each level must follow the formula for decagonal numbers to accurately map transaction relationship clusters in the fraud detection system.
    

    """
    return 4 * n * n - 3 * n