
    Design a function for the fraud detection system that calculates the number of transaction data points needed to complete the nth level of decagonal pattern analysis, where each level forms a decagonal arrangement of suspicious transaction clusters. The resulting value will determine the sample size required for comprehensive fraud pattern recognition at the specified analysis level.
    

    
def is_num_decagonal(n):
    """
    Design a function for the fraud detection system that calculates the number of transaction data points needed to complete the nth level of decagonal pattern analysis, where each level forms a decagonal arrangement of suspicious transaction clusters. The resulting value will determine the sample size required for comprehensive fraud pattern recognition at the specified analysis level.
    

    """
def is_num_decagonal(n):
    """
    Design a function for the fraud detection system that calculates the number of transaction data points needed to complete the nth level of decagonal pattern analysis, where each level forms a decagonal arrangement of suspicious transaction clusters. The resulting value will determine the sample size required for comprehensive fraud pattern recognition at the specified analysis level.
    

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