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 A280826 #10 Feb 16 2025 08:33:39
%S A280826 11,22,33,44,55,66,77,88,99,1002,1003,1004,1005,1006,1007,1008,1009,
%T A280826 1012,1013,1014,1015,1016,1017,1018,1019,1020,1021,1022,1030,1031,
%U A280826 1033,1040,1041,1044,1050,1051,1055,1060,1061,1066,1070,1071,1077,1080,1081,1088,1090,1091,1099,1102,1103,1104,1105,1106,1107,1108,1109
%N A280826 Numbers with an even number of digits and with an odd number of distinct digits.
%H A280826 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Digit.html">Digit</a>
%H A280826 <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.
%F A280826 A000035(A055642(a(n))) = 0.
%F A280826 A000035(A043537(a(n))) = 1.
%t A280826 Select[Range[1110], Mod[Length[IntegerDigits[#1]], 2] == 0 && Mod[Length[Union[IntegerDigits[#1]]], 2] == 1 & ]
%t A280826 endQ[n_]:=Module[{idn=IntegerDigits[n]},EvenQ[Length[idn]]&&OddQ[ Length[ Union[ idn]]]]; Select[Range[1200],endQ] (* _Harvey P. Dale_, Mar 31 2019 *)
%Y A280826 Cf. A000035, A001637, A043537, A055642, A280823, A280824, A280825.
%K A280826 nonn,base,easy
%O A280826 1,1
%A A280826 _Ilya Gutkovskiy_, Jan 08 2017