Artwork
The cover is a portion of an oil painting by Graham Coxon called Apprentice. The album's singles also have cover art by Coxon. The numbers 1 and 3 have been painted so they also form the letter 'B' - presumably for 'Blur'. This was not present on the original Apprentice, nor was the "shine" on the figure's head, which appears on 13. These additions were made long after the original Apprentice, which was painted in 1996. The band's logo does not appear on the album in any form, aside from a sticker on the CD packaging. The logo is also absent from the single covers.
Read more about this topic: 13 (Blur album)