This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A165500 #12 Sep 24 2018 02:40:25 %S A165500 1,2,3,2,5,3,7,4,2,5,11,3,13,7,6,2,17,3,19,5,7,11 %N A165500 Maximum length of arithmetic progression starting at n such that each term k has tau(k) = tau(n). %C A165500 Implicitly, we require the difference d of the arithmetic progression to be positive. %C A165500 a(n) <= n for all n. %e A165500 For n=4, tau(n)=3 so each term of the arithmetic progression must be the square of a prime. The difference d must be odd for n+d to qualify, in which case n+2d is even and does not qualify; so a(4)=2 is an upper bound. %Y A165500 Cf. A165498, A165501, A088430. %K A165500 hard,nonn,more %O A165500 1,2 %A A165500 _Hugo van der Sanden_, Sep 21 2009, Oct 09 2009 %E A165500 Extended to n=22 (taking advantage of A088430 for n=19) by _Hugo van der Sanden_, Jun 02 2015