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 A112756 #6 Feb 07 2020 09:03:55
%S A112756 1,3,5,3,5,5,3,5,5,3,5,5,5,3,5,5,5,5,3,5,5,5,5,3,5,5,5,5,5,3,5,5,5,5,
%T A112756 5,5,3,5,5,5,5,5,5,3,5,5,5,5,5,5,5,3,5,5,5,5,5,5,5,5,3,5,5,5,5,5,5,5,
%U A112756 5,3,5,5,5,5,5,5,5,5,5,3,5,5,5,5,5,5,5,5,5,5,3,5,5,5,5,5,5,5,5,5,5,3,5,5,5
%N A112756 Greatest prime factor of n-th number of the form 3^i*5^j.
%H A112756 Amiram Eldar, <a href="/A112756/b112756.txt">Table of n, a(n) for n = 1..10000</a>
%F A112756 a(n) = A006530(A003593(n));
%F A112756 A112755(n) <= a(n) <= 5.
%t A112756 s = {}; m = 12; Do[n = 5^k; While[n <= 5^m, AppendTo[s, n]; n *= 3], {k, 0, m}]; FactorInteger[#][[-1, 1]] & /@ Union[s] (* _Amiram Eldar_, Feb 07 2020 *)
%Y A112756 Cf. A003593, A006530, A086411, A112764, A112755.
%K A112756 nonn
%O A112756 1,2
%A A112756 _Reinhard Zumkeller_, Sep 18 2005