Whats the 17/0/13 on the anime page behind a file?

It provides information about the availability of that file. The color coding is the same as on the detailed file info page.
This means:

• blue = users having that file in their mylist
• black = users who deleted that file
• black(italic) = users with state unknown

Counts for the states on hdd and on cd are not shown.

Example:
10/3/2 == total users/deleted/unknown

This would mean:

10 users have this file in their mylist

3 users deleted the file

2 users have it on state unknown

10-3-2 = 5 have the file on hdd or on cd.

Note:

This info is generated by the filestates per file set in everyones mylist. These values are NOT generated automatically!