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 A033081 #10 Jul 28 2023 23:28:21
%S A033081 1,2,3,4,5,6,7,8,9,14,25,30,36,41,47,52,58,63,69,74,85,96,141,147,252,
%T A033081 258,303,363,369,414,474,525,585,630,636,696,741,747,852,858,963,969,
%U A033081 1414,1474,2525,2585,3030,3036,3630,3636,3696
%N A033081 Numbers in which all pairs of consecutive base-10 digits differ by 3.
%H A033081 Harvey P. Dale, <a href="/A033081/b033081.txt">Table of n, a(n) for n = 1..200</a>
%t A033081 Join[Range[9],Select[Range[4000],Union[Abs[Differences[ IntegerDigits[ #]]]] == {3}&]] (* _Harvey P. Dale_, Mar 10 2016 *)
%K A033081 nonn,base
%O A033081 1,2
%A A033081 _Clark Kimberling_