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 A192157 #6 Oct 21 2019 14:51:29
%S A192157 0,2,8,18,26,72,80,162,234,242,648,720,728,1458,2106,2178,2186,5832,
%T A192157 6480,6552,6560,13122,18954,19602,19674,19682,52488,58320,58968,59040,
%U A192157 59048,118098,170586,176418,177066,177138,177146,472392,524880,530712,531360
%N A192157 Monotonic ordering of nonnegative differences 3^i-9^j, for 40>=i>=0, j>=0.
%t A192157 c = 3; d = 9; t[i_, j_] := c^i - d^j;
%t A192157 u = Table[t[i, j], {i, 0, 40}, {j, 0, i*Log[d, c]}];
%t A192157 v = Union[Flatten[u ]]
%Y A192157 Cf. A192158.
%K A192157 nonn
%O A192157 1,2
%A A192157 _Clark Kimberling_, Jun 24 2011