It is a check digit, but it's just: n % 7. So ticket 98494660 has citation #984,946,605 Ticket 98494661 will have citation #984,946,616 (The example of the p

It is a check digit, but it's just: n % 7. So ticket 98494660 has citation #984,946,605 Ticket 98494661 will have citation #984,946,616 (The example of the pattern mistakenly starts with an citation number #984,946,606 which they said does not exist, rather than #984,946,605 which is the one shown in the image)