English

There are no Collatz-m-Cycles with $m\leq 91$

Number Theory 2023-04-05 v3

Abstract

The Collatz conjecture (or ``Syracuse problem'') considers recursively-defined sequences of positive integers where nn is succeeded by n2\tfrac{n}{2}, if nn is even, or 3n+12\tfrac{3n+1}{2}, if nn is odd. The conjecture states that for all starting values nn the sequence eventually reaches the trivial cycle 1,2,1,2,1, 2, 1, 2, \ldots . We are interested in the existence of nontrivial cycles. Let mm be the number of local minima in such a nontrivial cycle. Simons and de Weger proved that m76m \geq 76. With newer bounds on the range of starting values for which the Collatz conjecture has been checked, one gets m83m \geq 83. In this paper, we prove m92m \geq 92. The last part of this paper considers what must be proven in order to raise the number of odd members a nontrivial cycle has to have to the next bound -- that is, to at least K1.3751011K\geq1.375\cdot 10^{11}. We prove that it suffices to show that, for every integer smaller than or equal to 1536260=32691536\cdot2^{60}=3\cdot2^{69}, the respective Collatz sequence enters the trivial cycle. This reduces the range of numbers to be checked by nearly 6060\%.

Keywords

Cite

@article{arxiv.2201.00406,
  title  = {There are no Collatz-m-Cycles with $m\leq 91$},
  author = {Christian Hercher},
  journal= {arXiv preprint arXiv:2201.00406},
  year   = {2023}
}

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22 pages