Lower bounds for the total stopping time of 3X+1 iterates
Number Theory
2007-05-23 v1 Dynamical Systems
Abstract
The 3X+1 function T(n) is (3n+1)/2 if n is odd and n/2 if n is even. The total stopping time \sigma_\infty (n) for a positive integer n is the number of iterations of the 3x+1 function to reach 1 starting from n, and is \infty if 1 is never reached. The 3x+1 conjecture states that this function is finite. We show that infinitely many n have a finite total stopping time with \sigma_\infty(n) > 6.14316 log n. The proof uses a very large computation. It is believed that almost all positive integers have \sigma_\infty (n) > 6.95212 \log n. The method of the paper should extend to prove infinitely many integers have this property, but it would require a much larger computation.
Keywords
Cite
@article{arxiv.math/0103054,
title = {Lower bounds for the total stopping time of 3X+1 iterates},
author = {David Applegate and Jeffrey C. Lagarias},
journal= {arXiv preprint arXiv:math/0103054},
year = {2007}
}
Comments
21 pages latex, 1 figure