OFFSET
1,1
COMMENTS
a(n) is a lower bound on A284116(3n) (assuming that there is no starting string with an unbounded trajectory).
On October 30 2020, a student in my CS 360 class, Zhiping Cai, found that for n = 70051, 96938660265781 (96.9 trillion) steps are needed. See https://github.com/zcai1/posts-problem . I am not sure this has been independently verified. - Jeffrey Shallit, Sep 13 2021
LINKS
Lars Blomberg, Table of n, a(n) for n = 1..6075
CROSSREFS
KEYWORD
nonn
AUTHOR
Lars Blomberg and N. J. A. Sloane, Apr 19 2018
STATUS
approved