Superpermutation Almanac

Back to n = 13

W-0084

A superpermutation on 13 symbols, found by Jakub Halfar. It beat the previous record W-0075 by 521 letters and was the record on Nov 8, 2026. The next record W-0088 beat it by 22 letters.

Length
6,747,801,798
Repeated permutations
1,797,404
Received
Nov 8, 202615:33:19 UTC
Begins 0123456789ABC0123456789AB0C123456789AB01C23456789AB012C3456789AB0123C456789AB01234C56789AB012345C6789AB0123456C789AB0123…

Windows

6,747,801,786windows of 13 consecutive letters
=6,227,020,800distinct permutations
+1,797,404repeated permutations
+518,983,582windows that are not permutations

Detours by weight

A step is the move from one permutation in the superpermutation to the next permutation in it, and its weight is the number of letters added in that move. A detour starts at a step that differs from the next step of the recursive construction, and ends at the first permutation after that whose next step has weight 1. The weight of a detour is the number of letters added in it. After each detour, we consider the recursive construction to begin again from scratch at the permutation where the detour ends.

WeightDetours
10
20
311,695,375
43,921
51,503
61,232
7341
81,358
9453
10661
11104
12142
135

How it was found

From the submitter

Jay Pantone's 43/80 construction with my own selection of closed trails (different ones than in his words). The order and the cuts of the trails come from my segment insertion search on the GPU, plus two moves from the superpermutators group: William Echols's re-opening of a run of consecutive trails and Theo H.'s moving of a trail with a new phase. Published on 25 Oct 2026 in jhalfar/superpermutations as words/superpermutation-13-6747801798.spra.xz (Theo H.'s SPRA format).

Made with Claude (Opus 5.5) in Claude Code. I decide what to try, Claude writes the code and runs the searches.

Download

Learn about the Detour file format

Download Detour (.detour) 222.2 kB, or 6.7 GB decoded