W-0017
A superpermutation on 9 symbols, found by William Echols. It beat the previous record, W-0012, by 1 letter, and was the record for n = 9 from Jul 26 until Sep 29, 2026, when W-0029 was 229 letters shorter.
- Length
- 408,965
- Repeated occurrences
- 0
- Announced
- Jul 26, 2026
012345678012345670812345670182345670128345670123845670123485670123458670123456870123456078123456071823456071283456071238…
Windows
| 408,957 | windows of 9 consecutive letters | |
| = | 362,880 | distinct permutations, all 9! of them |
| + | 0 | repeated occurrences of a permutation |
| + | 46,077 | windows that are not permutations |
How it was found
Found in a session with GPT-5.6 in Codex; Echols later wrote that it came from lifting Raudvere's n = 8 word.
Checking
| Program | Source | Result | Time |
|---|---|---|---|
| permcheck | c46d3654 | all 362,880 permutations appear | under 1 s |
| literal_check | f4687121 | agrees on coverage | under 1 s |
Download
Download Detour (.detour) 836 bytes, or 409.0 kB decoded
Download text (.txt) 409.0 kB
# check it yourself
detour decode W-0017.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-0017.detour 408965
./target/release/bitmapcheck 9 ../W-0017.detour 408965
./target/release/wordhash 9 ../W-0017.detour 408965
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 46,031 tokens: 1 START, 1 literal of 1 byte in all, and 46,029 deviations. Deviations by weight, from 1 to 9: 0 · 46,025 · 4 · 0 · 0 · 0 · 0 · 0 · 0.