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 A071159 #22 Nov 20 2022 03:22:39
%S A071159 1,11,12,111,112,121,122,123,1111,1112,1121,1122,1123,1211,1212,1221,
%T A071159 1222,1223,1231,1232,1233,1234,11111,11112,11121,11122,11123,11211,
%U A071159 11212,11221,11222,11223,11231,11232,11233,11234,12111,12112,12121
%N A071159 Integers whose decimal expansion start with 1, do not contain zeros and each successive digit to the right is at most one greater than the previous digit.
%H A071159 Robert Israel, <a href="/A071159/b071159.txt">Table of n, a(n) for n = 1..10000</a>
%H A071159 S. Giraudo, <a href="http://arxiv.org/abs/1306.6938">Combinatorial operads from monoids</a>, arXiv preprint arXiv:1306.6938 [math.CO], 2013-2015. See Sect. 3.1.3.
%p A071159 R[1]:= [1]:
%p A071159 for d from 2 to 6 do
%p A071159 R[d]:= map(t -> seq(10*t+j,j=1..min((t mod 10)+1,9)), R[d-1])
%p A071159 od:
%p A071159 A:= map(op, [seq(R[d],d=1..6)]); # _Robert Israel_, Jan 31 2017
%t A071159 desQ[n_]:=Module[{idn=IntegerDigits[n]},idn[[1]]==1&&FreeQ[idn,0]&&Max[ Differences[ idn]]<2]; Select[Range[13000],desQ] (* _Harvey P. Dale_, Feb 19 2017 *)
%Y A071159 Essentially the same as A071157 but with digits reversed.
%Y A071159 Corresponding Łukasiewicz words: A071153.
%K A071159 nonn,base
%O A071159 1,2
%A A071159 _Antti Karttunen_, May 14 2002