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Skelet #17 and the fifth Busy Beaver number

Combinatorics 2024-07-04 v2 Logic

Abstract

We prove nonhalting of the Turing machine dubbed "Skelet #17", known to be one of the toughest 5-state, 2-symbol Turing machines to analyze. Combined with the efforts of The Busy Beaver Challenge, we are therefore able to show that BB(5), the fifth Busy Beaver number, equals 47,176,870.

Keywords

Cite

@article{arxiv.2407.02426,
  title  = {Skelet #17 and the fifth Busy Beaver number},
  author = {Chris Xu},
  journal= {arXiv preprint arXiv:2407.02426},
  year   = {2024}
}

Comments

added more references, fixed a broken link, and streamlined Proposition 3.4