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 A239086 #14 Jul 03 2022 20:11:41
%S A239086 1,2,3,4,5,6,7,8,9,10,12,11,13,14,15,16,17,18,19,20,21,23,22,24,25,26,
%T A239086 27,28,29,30,31,32,34,33,35,36,37,38,39,40,41,42,43,45,44,46,47,48,49,
%U A239086 50,51,52,53,54,56,55,57,58,59,60,61,62,63,64,65,67,66,68
%N A239086 The sequence S = a(1), a(2), ... is defined by a(1)=1, if d,e,f are consecutive digits then we do not have d < e = f, and S is always extended with the smallest integer not yet present in S.
%C A239086 Computed by Lars Blomberg.
%D A239086 Eric Angelini, Posting to Sequence Fans Mailing List, Sep 28 2013
%H A239086 Eric Angelini, <a href="http://www.cetteadressecomportecinquantesignes.com/LittleEqualGreat.htm">Less than <, Equal to =, Greater than ></a> (see sequence Se)
%H A239086 Eric Angelini, <a href="/A239083/a239083.pdf">Less than <, Equal to =, Greater than ></a> [Cached copy, with permission of the author]
%t A239086 a[1]=1;a[n_]:=a[n]=Block[{k=1},While[MemberQ[s=Array[a,n-1],k]||Or@@(#<#2==#3&@@@Partition[Flatten[IntegerDigits/@Join[s[[-2;;]],{k}]],3,1]),k++];k];Array[a,68] (* _Giorgos Kalogeropoulos_, May 14 2022 *)
%Y A239086 The sequences in this family are given in A239083-A239086, A239136-A239139, A239087-A239090, A239215-A239218, A239235.
%K A239086 nonn,base
%O A239086 1,2
%A A239086 _N. J. A. Sloane_, Mar 10 2014