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 A192172 #6 Oct 21 2019 15:05:36
%S A192172 0,6,9,36,84,96,99,744,936,984,996,999,5904,8976,9744,9936,9984,9996,
%T A192172 9999,34464,83616,95904,98976,99744,99936,99984,99996,99999,737856,
%U A192172 934464,983616,995904,998976,999744,999936,999984,999996,999999,5805696,8951424
%N A192172 Monotonic ordering of nonnegative differences 10^i-4^j, for 40>=i>=0, j>=0.
%t A192172 c = 10; d = 4; t[i_, j_] := c^i - d^j;
%t A192172 u = Table[t[i, j], {i, 0, 40}, {j, 0, i*Log[d, c]}];
%t A192172 v = Union[Flatten[u ]]
%Y A192172 Cf. A192171.
%K A192172 nonn
%O A192172 1,2
%A A192172 _Clark Kimberling_, Jun 24 2011