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 A044953 #7 Jun 22 2013 15:02:02
%S A044953 1,2,3,5,10,15,16,17,20,21,22,23,25,26,29,31,32,34,37,38,40,41,42,43,
%T A044953 46,47,48,51,53,55,58,59,60,61,62,63,64,69,81,84,85,86,87,89,93,101,
%U A044953 106,117,127,128,138,149,154,162,166,168,169,170
%N A044953 Numbers with no two equally numerous base 4 digits.
%t A044953 ntb4Q[n_]:=Module[{d=DeleteCases[DigitCount[n,4],0]},Length[d] == Length[ Union[d]]]; Select[Range[200],ntb4Q] (* _Harvey P. Dale_, Jun 22 2013 *)
%K A044953 nonn,base
%O A044953 1,2
%A A044953 _Clark Kimberling_