You are correct, Mike, they have the same rarity. Every stack of 1000 consecutively-numbered notes has one radar and one B-class repeater. The only reason repeaters are not worth as much is that they are not collected as widely as radars. I know my interest in B-class repeaters (i.e. of the form ABCXABC where X = any number, including A B or C) is very limited and I would only buy old notes that fit this category. A-class repeaters (i.e. of the form ABCABCA) are 1:10,000, and because they don't occur in every stack of notes, they should be worth more than radars. Again, though, radars are well-established as collectible numbers, repeaters are not. An article in the CPMS newsletter or an entry in Charlton would change that.
There you go, I'm starting to collect quite a few of these since they are simply cheaper to acquire. Collecting on a budget thing as common prefix fillers.
As a math lay person who is several levels below the math geek, A, B, or C class defintions seemed to be a nice simple convention I could get hold of. The A class as RP describes it ABCABCA makes sense to me just because of the odds alone.
B Class being the more common variety could be ABCXABC so long as X is and even number ;
(according to RP), so then what is a C class?
Also, I just saw a AB000AB on auction just recently, what kind of repeater would tha be?
Punkys Dad x Punkys Dad