27/09/2026
On September 16, 2011, an anonymous user posted a math question to the "/sci/" board of 4chan about The Melancholy of Haruhi Suzumiya, an anime series originally broadcast in nonlinear order, which had led fans to develop a habit of rewatching its 14 episodes in every possible sequence.
The question was simple to state and brutally hard to solve: what's the shortest possible string of episodes you'd need to watch to see the first season in every conceivable order? In mathematical terms, this is called a superpermutation, and finding a general formula for the shortest possible superpermutation of any size had stumped mathematicians for at least 25 years.
In under an hour, another anonymous poster replied with an answer, not a full solution, but a rigorous proof establishing a new lower bound. The proof showed that for a set of any size, and specifically for Haruhi's 14 episodes, a viewer would need to watch at least 93,884,313,611 episodes to see every possible ordering, roughly 4.3 million years of continuous viewing.
The post sat largely unnoticed outside anime fan circles for seven years. That changed in October 2018, when mathematician Robin Houston stumbled across the proof on a fan wiki and realized its significance, tweeting that the best known lower bound for this decades-old problem had been established by an anonymous poster on a board "mainly devoted to anime."
Houston, along with mathematicians Jay Pantone of Marquette University and Vince Vatter of the University of Florida, independently verified the anonymous proof and confirmed it held up to rigorous scrutiny. The timing lined up with a separate breakthrough from science fiction writer Greg Egan, who had just published a new upper bound for the same problem, drawing renewed attention to the puzzle as a whole.
When Houston, Pantone, and Vatter formally published their refined version of the proof, first in the On-Line Encyclopedia of Integer Sequences and later in an academic paper, they credited the original source exactly as it had appeared: listed as first author, "Anonymous 4chan Poster."