
    Write a function to analyze transaction sequences of length 2n where each transaction is marked as approved (1) or declined (0), and determine how many possible sequences exist where the count of approved transactions in the first n transactions equals the count in the last n transactions, as this pattern helps identify normal consumer behavior patterns.
    

    
def count_binary_seq(n):
    """
    Write a function to analyze transaction sequences of length 2n where each transaction is marked as approved (1) or declined (0), and determine how many possible sequences exist where the count of approved transactions in the first n transactions equals the count in the last n transactions, as this pattern helps identify normal consumer behavior patterns.
    

    """
def count_binary_seq(n):
    """
    Write a function to analyze transaction sequences of length 2n where each transaction is marked as approved (1) or declined (0), and determine how many possible sequences exist where the count of approved transactions in the first n transactions equals the count in the last n transactions, as this pattern helps identify normal consumer behavior patterns.
    

    """
    nCr = 1
    res = 1
    for r in range(1, n + 1):
        nCr = nCr * (n + 1 - r) / r
        res += nCr * nCr
    return res