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 A030143 #11 Feb 14 2017 23:07:42
%S A030143 0,2,4,6,8,10,12,14,16,18,30,32,34,36,38,50,52,54,56,58,70,72,74,76,
%T A030143 78,90,92,94,96,98,210,212,214,216,218,230,232,234,236,238,250,252,
%U A030143 254,256,258,270,272,274,276,278,290,292,294,296,298,410,412,414
%N A030143 Even numbers in which parity of digits alternates.
%H A030143 Reinhard Zumkeller, <a href="/A030143/b030143.txt">Table of n, a(n) for n = 1..10000</a>
%H A030143 <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.
%F A030143 (1 - a(n) mod 2) * A228710(a(n)) = 1. - _Reinhard Zumkeller_, Aug 31 2013
%t A030143 id[n_]:=IntegerDigits[n]; t={}; Do[If[Length[id[n]]==1, AppendTo[t,n],If[Union[Abs[Differences[Boole /@ EvenQ[id[n]]]]]=={1}, AppendTo[t,n]]], {n,0,414,2}]; t (* _Jayanta Basu_, May 07 2013 *)
%o A030143 (Haskell)
%o A030143 a030143 n = a030143_list !! (n-1)
%o A030143 a030143_list = filter even a030141_list
%o A030143 -- _Reinhard Zumkeller_, Aug 31 2013
%Y A030143 Cf. A030142, A062285, intersection of A005843 and A030141.
%K A030143 nonn,base,easy
%O A030143 1,2
%A A030143 _Patrick De Geest_
%E A030143 Offset corrected by _Reinhard Zumkeller_, Aug 31 2013