Here's a get to the patents endpoint for three plant patents.
I asked for the sort to be by patent number asc. It looks like an
alpha sort is being applied. The sql might need to be
"order by length(patent_number), patent_number"
Utility patents might have the same problem when the patent number
gets to 10,000,000. As I write this utility patent number 9,479,999 has been issued.