Superpermutation Almanac

n = 12

W-0051

A superpermutation on 12 symbols, found by Theo H.. It is listed as a notable word: it ties W-0049, the record at the time.

Length
522,745,531
Repeated occurrences
169,350
Announced
Oct 5, 2026
Begins 0123456789AB0123456789A0B123456789A01B23456789A012B3456789A0123B456789A01234B56789A012345B6789A0123456B789A01234567B89A0…

Why it is listed

Theo H.'s dynamic programme for where each closed trail opens, run on Halfar's 522,745,538; ties Halfar's word committed earlier.

Windows

522,745,520windows of 12 consecutive letters
=479,001,600distinct permutations, all 12! of them
+169,350repeated occurrences of a permutation
+43,574,570windows that are not permutations

How it was found

Theo H.'s dynamic programme for where each closed trail opens, run on Halfar's 522,745,538; ties Halfar's word committed earlier.

Checking

Total check time: 8 s, including preparation but not time in the queue.

ProgramSourceResultTime
classcheck41928cceall 479,001,600 permutations appear, by rotation class3 s
bitmapcheck288b3f67agrees, by Lehmer rank2 s
wordhash94925fe4the SHA-256 of the word and of its mirror3 s
SHA-256ef21d16324f88dcb1c3fc4117e086992e028e3449c88a2937f13b6b30a464e65 Compilerrustc 1.89.0 (29483883e 2025-08-04)

Download

Download Detour (.detour) 41.5 kB, or 522.7 MB decoded

Decode to text

# check it yourself
detour decode W-0051.detour - | tr -d '\n' | shasum -a 256
tar xzf checkers-rs-source.tar.gz && cd checkers-rs && cargo build --release --locked
./target/release/classcheck 12 ../W-0051.detour 522745531
./target/release/bitmapcheck 12 ../W-0051.detour 522745531
./target/release/wordhash 12 ../W-0051.detour 522745531

Decoding needs detour; see the Detour format for how to build and install it. The checkers are in checkers-rs-source.tar.gz, which needs Rust 1.89 or later; each one decodes the file itself, so the word is never written out.

The file's header gives n = 12 and sync exponent 0. The file has 4,904,455 tokens: 1 START, 1 literal of 1 byte in all, and 4,904,453 deviations. Deviations by weight, from 1 to 12: 169,346 · 1,354,738 · 3,379,998 · 79 · 82 · 103 · 28 · 20 · 37 · 12 · 9 · 1.