The Prime Numbers and the Prime Numbers Die-Cuts share serial numbers. The Die-Cut versions are always the first to be serial numbered, while the regular versions contain the latter part. For example, the Steve Yzerman trio of cards celebrates his 539 goals (at that point in his career) and all cards have a serial number out of 539. Die-Cut card #10a has a print run (PR) of 500, so cards with the serial numbers 001/539 - 500/539 are die cut, while the regular version cards 501/539 - 539/539, making a PR of 39. #10b has a PR split of 30/509 (001/539 - 030/539 are die-cut while 031/539 - 539/539 are regular), and the #10c PR split is 9/530 (001/539 - 009/539 are die-cut while 010/539 - 539/539 are regular). This is why the cards will show "SN539, PR###" in the Note, to help everyone understand exactly how many were die-cut and how many were not.