In a repeater how many repeating numbers can there be? Is this classed as a repeater of some sort...BKM6848404?

I slowly getting the hang of it and now I'm hooked at looking at all the serial numbers on the bills I get.

If 3473473 is a cycle 3

and 2424242 is a cycle 2

and 2345234 is a cycle 4, then...

6848404 is a cycle 7. Meaning, the entire series of 7 numbers could only be shown to repeat if the entire 7 numbers were laid down again beside.

"7 digit repeater"