I would say its "fancy" if you like it. So are "broken ladders," "near solids" & any "birthday #" note if you like it. The idea of a "fancy" serial number came from "planet
ebay." I would hazard to say that a FEW are cool, & may be significant to some (- like an area code 0090500) but not all collectors. It's definitely a niche place within the hobby & something new collectors need to be wary of & that's b/c no real premium unless you're willing to pay one. This is the realm of complete speculation.
Don't confuse the notion of "fancy" with "Special Serial Numbers," which are listed at the end of most currency catalogues. There should be no novel adverb (an unlisted adjective like "
mixed" or "broken" before the special # term (radar or ladder) unless it qualifies a type (like "2 digit/solid" before "radar"). Special Serials command a premium b/c they're very tough to source (& everyone will agree on this).
Special Serial Numbers are:
Radars: 1111111 or 1222221; 1234321 (aka: palindrome which reads the same both ways)
Ladders: 1234567 or 8765432
Repeaters: 1231231 or 7897897 (repeating pattern/ could have a "repeater radar"*)
Low Serial Numbers:for BoC a number below 1000
Million # notes: 1000000, 2000000, etc to 9000000
Binary Notes (Zeros & Ones)
Rotator Notes (also called SWIMS) these numbers read the same either right side up or upside down & use only digits 0, 6, 8 and 9: 9000006 8860988 0068900 etc
(* you can have different types of radars: these include a repeater, ladder & rotator type radar)
Hope that clarifies things.