Where, b is the latest patent number table (*** 12 digits, plus a decimal point) launched in 2003.10/.
Year number (4 digits)+patent type (5 digits)+serial number+computer check digit (dot after 1 digit)
A is the previous standard, 8 digits. The first two digits are the year number, the third digit is the patent type, followed by the serial number.
The above indicates the type of patent, 1 stands for invention, 2 stands for utility model and 3 stands for design.
C unknown, but definitely not the patent number or patent contribution number of China.