Lazy Beaver: Difference between revisions

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LB(n, m) is the smallest k > 0 such that no n-state, m-symbol [[Turing machine]] halts in exactly k steps.
LB(n, m) is the smallest k > 0 such that no n-state, m-symbol [[Turing machine]] halts in exactly k steps.
Unlike the variant that uses score, LB is computable. This is because the number of steps taken before halting is a syntactic property, so Rice's theorem does not apply.


== Computed Values ==
== Computed Values ==
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[[category:Functions]]
[[category:Functions]]


* https://oeis.org/A337805
* https://oeis.org/A337805: LB(n, 2)

Latest revision as of 04:06, 9 October 2026

The Lazy Beaver function is a computable variation of the Busy Beaver function defined by Scott Aaronson in his 2020 review.

LB(n, m) is the smallest k > 0 such that no n-state, m-symbol Turing machine halts in exactly k steps.

Unlike the variant that uses score, LB is computable. This is because the number of steps taken before halting is a syntactic property, so Rice's theorem does not apply.

Computed Values

Values found by Terry and Shawn Ligocki in 2021:

LB(n, m)
2-state 3-state 4-state 5-state 6-state
2-symbol 7 22 72 427 8,407
3-symbol 23 351 189,270
4-symbol 93 242,789
5-symbol 956
6-symbol 33,851

See Also