combinations mathematically. More recently, cities have taken to having the third letter alone being a letter, the rest numbers. Permitted alphanumeric combinations per GA36-2014 standard are listed in the table below. Should the number of combinations issued exceed 60% of the theoretical capacity of its type, the combination next in the list may be put into use after approval from the Vehicle Management Office of the provincial Public Security authority and reporting to the Vehicle Management Office of the Ministry of Public Security. Note: Y and N in this table reflects whether or not this combination type may be used in registration plates with 4 or 5 places for digits/numbers, while D and L represents any permitted digit or letter respectively. The numbers are produced at random, and are computer-generated at the issuing office. Numbers with a sequence of 6s, 8s, or 9s are usually considered to be lucky, therefore special sequences like "88888" or "86888" can be purchased through auction. A previous licence plate system, with a green background and the full name of the province in Chinese characters, actually had a sequential numbering order, and the numbering system was eventually beset with corruption. License plates have different formats that are issued to different vehicles: Since October 2007, black plates are no longer issued for vehicles belonging to foreigners, as this was "deemed discriminatory" and instead standard looking blue plates are now issued. However, foreigners still are issued a separate dedicated letter/number sequence to denote that they are a foreign owned/registered vehicle—e.g. in Beijing, the foreign owned plates are in the , , and sequence. The black plates are still issued to those who registered in both Mainland China and Hong Kong or Macau, specifically in Guangdong province, which are in the sequence of 粤Z·####港/澳. Registration combinations of written-off vehicles may be "recycled", or used again on a different vehicle only after 6 months from the write-off according to relevant regulations, but as a matter of fact, certain serials of number like 京A·##### in Beijing is not available for general public once recycled for unspecified reasons. In 2015, a former Commissioner of Beijing Traffic Management Bureau, the traffic branch of Beijing Municipal Public Safety Bureau, was sentenced for life, having been found guilty of corruption relating to fraud in issuing these licence plate combinations. Police Service, Armed Police Force, and Military Licence plates for China's Police Service, Armed Police