W-0072
A superpermutation on 14 symbols, found by William Echols. It beat the previous record, W-0070, by 131,516 letters, and was the record for n = 14 from Oct 19 until Oct 20, 2026, when W-0076 was 91 letters shorter.
- Length
- 93,904,804,516
- Repeated occurrences
- 19,588,088
- Announced
- Oct 19, 2026
0123456789ABCD0123456789ABC0D123456789ABC01D23456789ABC012D3456789ABC0123D456789ABC01234D56789ABC012345D6789ABC0123456D7…
Windows
| 93,904,804,503 | windows of 14 consecutive letters | |
| = | 87,178,291,200 | distinct permutations, all 14! of them |
| + | 19,588,088 | repeated occurrences of a permutation |
| + | 6,706,925,215 | windows that are not permutations |
How it was found
The openings and joins of the groups of his 93,904,936,032 optimized with GPT-6.1 Sol, on the same selection (Halfar's selection C); 131,516 shorter. Published only as a recipe (93904804516.spg.xz and decode.py).
Checking
Total check time: 26 min 11 s, including preparation but not time in the queue.
| Program | Source | Result | Time |
|---|---|---|---|
| classcheck | 41928cce | all 87,178,291,200 permutations appear, by rotation class | 11 min 15 s |
| bitmapcheck | 288b3f67 | agrees, by Lehmer rank | 7 min 12 s |
| wordhash | 94925fe4 | the SHA-256 of the word and of its mirror | 7 min 43 s |
Download
Download Detour (.detour) 4.7 MB, or 93.9 GB decoded
# check it yourself
detour decode W-0072.detour - | tr -d '\n' | shasum -a 256
tar xzf checkers-rs-source.tar.gz && cd checkers-rs && cargo build --release --locked
./target/release/classcheck 14 ../W-0072.detour 93904804516
./target/release/bitmapcheck 14 ../W-0072.detour 93904804516
./target/release/wordhash 14 ../W-0072.detour 93904804516
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 = 14 and sync exponent 21. The file has 686,462,983 tokens: 1 START and 686,462,982 deviations, with 327 SYNC tokens besides. Deviations by weight, from 1 to 14: 19,588,088 · 195,880,870 · 470,971,979 · 12,068 · 3,376 · 2,335 · 657 · 1,178 · 510 · 937 · 606 · 183 · 178 · 17.