
    Write a function to determine how many possible credit behavior patterns exist over a 2n-month period where the number of months with good payment standing in the first n months equals the number of months with good payment standing in the last n months. Each month is represented as either good standing (1) or missed payment (0), and the pattern must demonstrate balanced credit behavior between the two periods.
    

    
def count_binary_seq(n):
    """
    Write a function to determine how many possible credit behavior patterns exist over a 2n-month period where the number of months with good payment standing in the first n months equals the number of months with good payment standing in the last n months. Each month is represented as either good standing (1) or missed payment (0), and the pattern must demonstrate balanced credit behavior between the two periods.
    

    """
def count_binary_seq(n):
    """
    Write a function to determine how many possible credit behavior patterns exist over a 2n-month period where the number of months with good payment standing in the first n months equals the number of months with good payment standing in the last n months. Each month is represented as either good standing (1) or missed payment (0), and the pattern must demonstrate balanced credit behavior between the two periods.
    

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