Improved Bounds for Functions Related to Busy Beavers

@article{BenAmram2001ImprovedBF,
  title={Improved Bounds for Functions Related to Busy Beavers},
  author={Amir M. Ben-Amram and Holger Petersen},
  journal={Theory of Computing Systems},
  year={2001},
  volume={35},
  pages={1-11}
}
Abstract. Consider Turing machines that use a tape infinite in both directions, with the tape alphabet {0,1} . Rado's busy beaver function, ones(n), is the maximum number of 1's such a machine, with n states, started on a blank (all-zero) tape, may leave on its tape when it halts. The function ones(n) is non-computable; in fact, it grows faster than any computable function. Other functions with a similar nature can be defined also. All involve machines of n states, started on a blank tape. The… 
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