Back when GNUCitizen posted about this, a small tool was posted to calculate all possible combo's. The problem is that there is just such a vast number of possibilities.
As you can tell, each year, there are a maximum of ~2.4 million possible serial numbers, taking up 351MB of HDD space. In order to save processing power and time, I've created a program that pre-calculates all the possible combinations, resulting in over 11GB of data.
To give you an idea how much calculation it takes, here's a screenshot of the CPU load while calculating (it took an entire evening to create the new database with improvements for the new server).