It reminds me a bit of the quest to find 'God's Number' for the minimum number of moves such that you can always solve a Rubik's Cube. In that, the upper and lo

It reminds me a bit of the quest to find 'God's Number' for the minimum number of moves such that you can always solve a Rubik's Cube. In that, the upper and lower bounds were pushed closer and closer by proofs until finally they met- meaning the number 20 was exactly the answer. (Well, the lower bound was 20 for years, and the upper bound was pushed down over time). > Within a day or two, he had come up with a new upper bound on the length of the shortest superpermutation for n symbols: n! + (n – 1)! + (n – 2)! + (n – 3)! + n – 3 > The anonymous 4chan poster’s lower bound, meanwhile, was tantalizingly close to the new upper bound: It works out to n! + (n – 1)! + (n – 2)! + n – 3 IE: The upper bound has been lowered to n! + (n – 1)! + (n – 2)! + (n – 3)! + n – 3 The lower bound has been raised to n! + (n – 1)! + (n – 2)! + n – 3 If the mathematicians can get either number closer by (n-3)!, then they have it.