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 A032861 #22 Aug 22 2021 09:21:01
%S A032861 0,1,2,3,4,5,6,12,13,18,19,20,24,25,26,27,30,31,32,33,34,37,38,39,40,
%T A032861 41,73,74,75,76,77,80,81,82,83,109,110,111,112,113,116,117,118,119,
%U A032861 123,124,125,145,146,147,148,149,152,153,154,155
%N A032861 Numbers whose base-6 representation Sum_{i=0..m} d(i)*6^i has d(m) > d(m-1) < d(m-2) > ...
%t A032861 sdQ[n_]:=Module[{s=Sign[Differences[IntegerDigits[n,6]]]},s==PadRight[{}, Length[ s],{-1,1}]]; Select[Range[0,200],sdQ] (* _Harvey P. Dale_, Dec 15 2017 *)
%Y A032861 Cf. A007092.
%Y A032861 Cf. A032858..A032865 for bases 3..10.
%Y A032861 Cf. A306106..A306111 and A297147 for bases 3..9 and 10.
%K A032861 nonn,base
%O A032861 1,3
%A A032861 _Clark Kimberling_
%E A032861 a(1)=0 inserted by _Georg Fischer_, Dec 18 2020