Just in case you haven't already worked it out, this is NOT a number!!!
It is in fact a cryptic way that Brent signs his cartoons. (Yes, it's a B&H.)
Sometimes Brent might be drawing a lot of cartoons in one day and this is the
fastest way he knows how to sign things. He also signs many of his paintings and original artwork this way too.
You may have a book or something with cartoons in it. See if it has a 131.1 next to the artwork.
If it does, it's one of his.
Now you know how Brent signs his work, help spread the word...