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 A086411 #17 Jun 06 2024 15:08:14
%S A086411 1,2,3,2,3,2,3,3,2,3,3,3,2,3,3,3,2,3,3,3,3,2,3,3,3,3,3,2,3,3,3,3,3,2,
%T A086411 3,3,3,3,3,3,2,3,3,3,3,3,3,2,3,3,3,3,3,3,3,2,3,3,3,3,3,3,3,3,2,3,3,3,
%U A086411 3,3,3,3,3,2,3,3,3,3,3,3,3,3,3,2,3,3,3,3,3,3,3,3,3,3,2,3,3,3,3,3,3,3
%N A086411 Greatest prime factor of 3-smooth numbers.
%H A086411 Amiram Eldar, <a href="/A086411/b086411.txt">Table of n, a(n) for n = 1..10000</a>
%F A086411 a(n) = A006530(A003586(n)).
%F A086411 A086410(n) <= a(n) <= 3.
%F A086411 a(A033845(n)) = A086410(A033845(n))+1; a(A006899(n)) = A086410(A006899(n)). - _Reinhard Zumkeller_, Sep 25 2008
%F A086411 Conjecture: a(n) = A049237(n+1) for n>1. - _R. J. Mathar_, Jun 06 2024
%t A086411 Reap[Do[p = FactorInteger[n][[-1, 1]]; If[p < 5, Sow[p]], {n, 1, 2*10^5}] ][[2, 1]] (* _Jean-François Alcover_, Dec 17 2017 *)
%Y A086411 Cf. A003586, A006530, A006899, A033845, A086410.
%K A086411 nonn
%O A086411 1,2
%A A086411 _Reinhard Zumkeller_, Jul 18 2003