OFFSET
2,2
COMMENTS
a(1) is not well defined, since the maximal progression has only one term.
EXAMPLE
For n=6, A165500(n)=3, and the least difference d such that tau(6) = tau(6+d) = tau(6+2d) is d=2, so a(6)=2.
CROSSREFS
KEYWORD
hard,nonn,more
AUTHOR
Hugo van der Sanden, Sep 21 2009, Oct 09 2009
EXTENSIONS
Extended to n=22 taking advantage of A088430 for n=19, Hugo van der Sanden, Jun 02 2015
STATUS
approved