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 A043160 #14 Nov 11 2022 14:05:32
%S A043160 11,25,75,88,139,153,200,217,267,281,331,345,395,409,459,473,523,537,
%T A043160 587,600,651,665,704,779,793,843,857,907,921,971,985,1035,1049,1099,
%U A043160 1112,1163,1177,1224,1241,1291,1305,1355,1369,1419,1433,1483,1497,1547,1561
%N A043160 Numbers k such that 1 and 3 occur juxtaposed in the base-8 representation of k but not of k-1.
%H A043160 Michael S. Branicky, <a href="/A043160/b043160.txt">Table of n, a(n) for n = 1..10000</a>
%t A043160 SequencePosition[Table[If[SequenceCount[IntegerDigits[n,8],{1,3}]>0 || SequenceCount[ IntegerDigits[n,8],{3,1}]>0,1,0],{n,1600}],{0,1}][[All,2]] (* _Harvey P. Dale_, Nov 11 2022 *)
%o A043160 (Python)
%o A043160 def has13or31(n): o = oct(n); return "13" in o or "31" in o
%o A043160 def ok(n): return has13or31(n) and not has13or31(n-1)
%o A043160 print([k for k in range(1600) if ok(k)]) # _Michael S. Branicky_, Nov 25 2021
%Y A043160 Cf. A007094, A043940.
%K A043160 nonn,base
%O A043160 1,1
%A A043160 _Clark Kimberling_