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 A084789 #7 Jan 30 2020 06:41:19
%S A084789 1,4,9,12,18,36,81,108,162,256,288,324,512,576,648,768,864,1024,1152,
%T A084789 1296,1536,1728,2304,2592,3072,3456,4608,5184,6912,9216,10368,13824,
%U A084789 20736,27648,41472,82944,165888,196608,221184,262144,294912,331776
%N A084789 Increasing gaps between 3-smooth numbers (lower end).
%H A084789 Amiram Eldar, <a href="/A084789/b084789.txt">Table of n, a(n) for n = 1..10000</a>
%F A084789 a(n) = A084790(n) - A084788(n).
%F A084789 a(n) = A003586(A084791(n)).
%t A084789 s = {}; m = 13; Do[n = 3^k; While[n <= 3^m, AppendTo[s, n]; n*=2], {k, 0, m}]; s = Union[s]; d = Differences @ s; v = DeleteDuplicates @ FoldList[Max, d]; Map[s[[First@ Position[d, #]]] &, v] //Flatten (* _Amiram Eldar_, Jan 30 2020 *)
%Y A084789 Cf. A003586, A061987, A084788, A084790, A084791.
%K A084789 nonn
%O A084789 1,2
%A A084789 _Reinhard Zumkeller_, Jun 03 2003