If we're talking technically it looks more like a 7 digit repeater then a 4 digit repeater. The truth is it would take at a minimum a second note to show only half of the full cycle of a 4 digit repeater and that means one would have a 1 out of 10 odds based on the first digit alone that the second note would continue this cycle.
Their can technically be only 3 repeaters that can be confirmed with 1 banknote, Solid, 2 Digit Radar Repeater and the 3 digit Repeater. Any repeater beyond a 3 Digit Repeater would require additional notes to show the continuation of the pattern.
I sort of get what you are saying here, except the part about the 7 digit repeater. Every Canadian note is a 7 digit repeater in a weird kind of way. But the point is taken that Canadian notes, with their 7-digit serial numbers, can't finish on a full cycle of the sequence of digits that is repeating. In other words, there's always going to be a digit missing at the end (except with solid repeaters, of course).
Because of the missing digit problem, this is why I consider a Class B repeater (or Cycle-4 repeater, as they are called in the catalogue) a 3 digit repeater. The fourth digit in the repeating sequence is not present on the note, so can't really be said to be repeating. It's just the first three numbers of the 7-digit serial number that repeats.
U.S. notes, with their 8-digit serial numbers, create a lot more complete repeating patterns. And, of course, there's very little overlap between radars and repeaters.
7444744 is still a binary Class B repeater. I use the word "binary" here to mean "composed of two different digits", even though some people object to that. The binary code used by computers is popularly represented by the digits 0 and 1, but a binary system could be made of any two variables. Like 5 and 6, A and B, on and off, etc.
Canadian Paper Money
