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 A192158 #6 Oct 21 2019 14:51:49
%S A192158 0,6,8,54,72,78,80,486,648,702,720,726,728,4374,5832,6318,6480,6534,
%T A192158 6552,6558,6560,39366,52488,56862,58320,58806,58968,59022,59040,59046,
%U A192158 59048,354294,472392,511758,524880,529254,530712,531198,531360,531414,531432
%N A192158 Monotonic ordering of nonnegative differences 9^i-3^j, for 40>= i>=0, j>=0.
%t A192158 c = 9; d = 3; t[i_, j_] := c^i - d^j;
%t A192158 u = Table[t[i, j], {i, 0, 40}, {j, 0, i*Log[d, c]}];
%t A192158 v = Union[Flatten[u ]]
%Y A192158 Cf. A192157.
%K A192158 nonn
%O A192158 1,2
%A A192158 _Clark Kimberling_, Jun 24 2011