puzzle-time
Explanation
The Joke
The comic presents itself as a classic puzzle page, with the header "PUZZLE TIME!" and a number sequence: 0, 1, 4, -13, -133, 52, 53, -155... The reader is asked "What is the pattern of this sequence?" with the note "(Answer on bottom of page)" inviting them to try to find the pattern before checking.
The sequence is deliberately nonsensical -- there is no discernible mathematical pattern connecting these numbers. After the reader presumably spends time trying to crack the code, the answer at the bottom of the page (printed upside down, as is traditional for puzzle pages) reads: "EVERY NUMBER WAS READ BY A DICKHEAD."
The Humor
The joke works on multiple levels. First, it parodies the format of newspaper and magazine puzzle pages that present number sequences and challenge readers to find the pattern. Second, it exploits the human tendency to search for patterns even where none exist -- anyone who spent time trying to work out the relationship between these numbers has been pranked. The upside-down answer is the final twist: instead of a satisfying mathematical revelation, the reader gets an insult for having bothered to look. The comic is essentially a meta-joke about the reader themselves, making anyone who engaged with the puzzle the butt of the joke.
References
Number sequence puzzles are a common feature of IQ tests and recreational mathematics. The joke also touches on apophenia -- the human tendency to perceive meaningful patterns in random data.