Superpermutation Almanac

n = 9

W-0037

A superpermutation on 9 symbols, found by Jay Pantone jaypantone. It beat the previous record, W-0029, by 4 letters, and was the record for n = 9 from Oct 1 until Oct 2, 2026, when W-0038 was 1 letter shorter.

Length
408,732
Repeated occurrences
336
Announced
Oct 1, 2026
Begins 012345678012345670812345670182345670128345670123845670123485670123458670123456870123456078123456071823456071283456071238…

Windows

408,724windows of 9 consecutive letters
=362,880distinct permutations, all 9! of them
+336repeated occurrences of a permutation
+45,508windows that are not permutations

How it was found

Local improvement of the September 29 word, found by two Claude Opus 5.5 instances and two Astra 6 instances working together.

Checking

Total check time: under 1 s, including preparation but not time in the queue.

ProgramSourceResultTime
classcheck41928cceall 362,880 permutations appear, by rotation classunder 1 s
bitmapcheck288b3f67agrees, by Lehmer rankunder 1 s
wordhash94925fe4the SHA-256 of the word and of its mirrorunder 1 s
SHA-25619a0dc3ef2bf324374a3da7964100787011d42973211f05395d6b7ade9252320 Compilerrustc 1.89.0 (29483883e 2025-08-04)

Download

Download Detour (.detour) 496 bytes, or 408.7 kB decoded

Download text (.txt) 408.7 kB

Decode to text

# check it yourself
detour decode W-0037.detour - | tr -d '\n' | shasum -a 256
tar xzf checkers-rs-source.tar.gz && cd checkers-rs && cargo build --release --locked
./target/release/classcheck 9 ../W-0037.detour 408732
./target/release/bitmapcheck 9 ../W-0037.detour 408732
./target/release/wordhash 9 ../W-0037.detour 408732

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 = 9 and sync exponent 0. The file has 6,756 tokens: 1 START, 1 literal of 1 byte in all, and 6,754 deviations. Deviations by weight, from 1 to 9: 336 · 1,680 · 4,687 · 4 · 4 · 39 · 3 · 1 · 0.