W-0014
A superpermutation on 7 symbols, found by Robin Houston and Greg Egan. It beat the previous record, W-0013, by 1 letter, and was the record for n = 7 from Mar 2, 2019 until Aug 17, 2026, when W-0021 was 1 letter shorter.
- Length
- 5,906
- Repeated occurrences
- 0
- Announced
- Mar 2, 2019
012345601234506123450162345012634502163450261345026314502634150263451026345012364502136450231645023614502364150236451023…
Windows
| 5,900 | windows of 7 consecutive letters | |
| = | 5,040 | distinct permutations, all 7! of them |
| + | 0 | repeated occurrences of a permutation |
| + | 860 | windows that are not permutations |
How it was found
Egan's search program completed Houston's palindromic non-standard kernel 666646664466646666 with 2-cycles, imposing the kernel's twofold symmetry.
Checking
| Program | Source | Result | Time |
|---|---|---|---|
| permcheck | c46d3654 | all 5,040 permutations appear | under 1 s |
| literal_check | f4687121 | agrees on coverage | under 1 s |
Download
Download Detour (.detour) 412 bytes, or 5.9 kB decoded
Download text (.txt) 5.9 kB
# check it yourself
detour decode W-0014.detour - | tr -d '\n' | shasum -a 256
tar xzf checkers-rs-source.tar.gz && cd checkers-rs && cargo build --release --locked
./target/release/classcheck 7 ../W-0014.detour 5906
./target/release/bitmapcheck 7 ../W-0014.detour 5906
./target/release/wordhash 7 ../W-0014.detour 5906
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 = 7 and sync exponent 0. The file has 767 tokens: 1 START, 1 literal of 1 byte in all, and 765 deviations. Deviations by weight, from 1 to 7: 0 · 752 · 13 · 0 · 0 · 0 · 0.