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 A130890 #2 Mar 30 2012 18:50:58
%S A130890 4,23,281,2825,28287,282890,2828964,28289682,282896825
%N A130890 Number of terms of A061681 having length = n in decimal representation.
%C A130890 A055642(a(n)) = n; a(n) / A130901(n) --> 1.
%e A130890 a(1)=#{1,2,4,8}=4;
%e A130890 a(2)=#{16,17,18,19,20,22,24,26,28,30,33,36,39,42,46,50,55,60,66,72,79,86,94}=23.
%K A130890 nonn,base,more
%O A130890 1,1
%A A130890 _Reinhard Zumkeller_, Jun 08 2007