W-0050

A superpermutation on 13 symbols, found by Jakub Halfar. It beat the previous record, W-0043, by 88 letters, and was the record for n = 13 from Oct 4 until Oct 5, 2026, when W-0054 was 472 letters shorter.

Length: 6,747,917,970
Repeated occurrences: 1,693,436
Announced: Oct 4, 2026

Begins

0123456789ABC0123456789AB0C123456789AB01C23456789AB012C3456789AB0123C456789AB01234C56789AB012345C6789AB0123456C789AB0123…

Windows

	6,747,917,958	windows of 13 consecutive letters
=	6,227,020,800	distinct permutations, all 13! of them
+	1,693,436	repeated occurrences of a permutation
+	519,203,722	windows that are not permutations

How it was found

Published first as a plan with the word's SHA-256; the compressed word followed at 01:40 UTC on Oct 5.

Checking

Total check time: 1 min 50 s, including preparation but not time in the queue.

Program	Source	Result	Time
classcheck	41928cce	all 6,227,020,800 permutations appear, by rotation class	42 s
bitmapcheck	288b3f67	agrees, by Lehmer rank	32 s
wordhash	94925fe4	the SHA-256 of the word and of its mirror	35 s

SHA-25636cc5f50bf4d26c87579f6e58f135643fdb45662aad39f8bd198604d2f541a15 Compilerrustc 1.89.0 (29483883e 2025-08-04)

Download

Download Detour (.detour) 239.2 kB, or 6.7 GB decoded

Decode to text

# check it yourself
detour decode W-0050.detour - | tr -d '\n' | shasum -a 256
tar xzf checkers-rs-source.tar.gz && cd checkers-rs && cargo build --release --locked
./target/release/classcheck 13 ../W-0050.detour 6747917970
./target/release/bitmapcheck 13 ../W-0050.detour 6747917970
./target/release/wordhash 13 ../W-0050.detour 6747917970

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 = 13 and sync exponent 0. The file has 54,104,562 tokens: 1 START, 1 literal of 1 byte in all, and 54,104,560 deviations. Deviations by weight, from 1 to 13: 1,693,436 · 15,240,864 · 37,168,039 · 280 · 372 · 430 · 618 · 214 · 54 · 70 · 88 · 68 · 27.