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 A043500 #17 Apr 16 2023 16:38:54 %S A043500 2222,12222,20222,21222,22022,22122,22202,22212,22220,22221,22223, %T A043500 22224,22225,22226,22227,22228,22229,22232,22242,22252,22262,22272, %U A043500 22282,22292,22322,22422,22522,22622,22722,22822,22922 %N A043500 Numbers having four 2's in base 10. %H A043500 Daniel Starodubtsev, <a href="/A043500/b043500.txt">Table of n, a(n) for n = 1..10000</a> %t A043500 Select[Range[2222,30000],DigitCount[#,10,2]==4&] (* _Harvey P. Dale_, Oct 05 2012 *) %Y A043500 Cf. A043496. %K A043500 nonn,base %O A043500 1,1 %A A043500 _Clark Kimberling_