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 A031943 #15 Aug 22 2021 00:11:34
%S A031943 1,2,3,4,5,7,8,9,10,11,13,14,15,16,17,19,20,21,22,23,26,27,28,29,35,
%T A031943 36,38,39,40,41,42,44,45,46,47,48,51,52,53,54,55,57,58,59,65,66,67,69,
%U A031943 70,71,72,73,76,77,78,79,80,82,83,84,85,86,88
%N A031943 Numbers with no consecutive equal base-5 digits.
%F A031943 A031943 = { n | A043279(n)=1 } = A043091 \ {0}. - _M. F. Hasler_, Jul 23 2013
%t A031943 Select[Range[90],FreeQ[Differences[IntegerDigits[#,5]],0]&] (* _Harvey P. Dale_, Nov 30 2019 *)
%Y A031943 Cf. A000975 (base-2 analog), A031941 or A043089 (base-3 analog), A031942 or A043090 (base-4 analog), A043092, ..., A043096 (base-6 through base-10 analog).
%K A031943 nonn,base
%O A031943 1,2
%A A031943 _Clark Kimberling_