The question is about "superpermutations". The permutations of 1 and 2 are "12" and "21". A "superpermutation" would be "1221". It contains the numbers 1 and 2 as well as all permutations of 1 and 2. However "121" is also a superpermutation of 1 and 2. It also contains "12" and "21" and it's shorter than "1221".

The problem is finding the shortest superpermutation. Stand-up Maths has a video where he interviews a mathematician that published Anonymous' solution. So yes, there is a math paper where the main author is "Anonymous 4chan Poster".