> <http://domain.com/folder/folder2/folder3/id/1.html>
> ....
> <http://domain.com/folder/folder2/folder3/id/500.html>

Number sequences: How to mirror only files/URLs using a certain ID/number
range - <http://httrack.kauler.com/help/URL_number_sequences>

Either paste in the url box or use action=get seperated
url=file:\\\c:\path\to\file.txt