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 A043941 #14 Feb 10 2024 16:01:36
%S A043941 12,33,76,103,140,161,204,225,271,289,332,353,396,417,460,481,524,545,
%T A043941 588,615,652,673,716,737,831,844,865,908,929,972,993,1036,1057,1100,
%U A043941 1127,1164,1185,1228,1249,1295,1313,1356,1377
%N A043941 Numbers k such that 1 and 4 occur juxtaposed in the base-8 representation of k but not of k+1.
%H A043941 Harvey P. Dale, <a href="/A043941/b043941.txt">Table of n, a(n) for n = 1..1000</a>
%t A043941 SequencePosition[Table[If[SequenceCount[IntegerDigits[n,8],{1,4}]>0 || SequenceCount[ IntegerDigits[n,8],{4,1}]>0 ,1,0],{n,1500}],{1,0}][[;;,1]] (* _Harvey P. Dale_, Feb 10 2024 *)
%Y A043941 Cf. A007094.
%K A043941 nonn,base
%O A043941 1,1
%A A043941 _Clark Kimberling_