I know this isn't anything special, but it is very rare that I see a serial number even this interesting. So, I thought I would post a pic
It's called a Ladder note. Each number is the same or higher as it reads left to right. It's a little extra special because the numbers are in order, 23456, they didn't skip or jump a number.
If it's interesting for you then we're happy to have you share it with us. Don't ever be bashful about posting what "floats your boat".
I admit I do not often look at the numbers on my notes, but when I do they are typically nothing interesting. Picked this one out to pay for something and decided to keep it because it was unusual