Downloading from pattern URL?

Hello,

I am a researcher, and I often find myself downloading files from a pattern URL, for images of books. For example, kind of like website.com/files/book3/page{ccc} where the {ccc} is a counter, and will download every file until it reaches an invalid link, signifying the end of the book.

I have yet to find an extension like this for safari... Google Chrome has one which works nicely, named Simple Mass Downloader but I prefer safari. Does anyone know of an extension which could perform this function? I tried many searches but did not find one with this capability.

Thank you so much!