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 A141470 #3 Mar 30 2012 18:51:58 %S A141470 0,1,1,1,2,3,4,3,1,7,1,4,6,7,10,7,16,5,9,11,3,22,5,17,14,12,7,21,20,1, %T A141470 25,9,21,7,4,22,13,14,18,33,35,20,13,53,51,19,7,46,52,3,5,9,12,42,12, %U A141470 17,34,22,55,51,57,31,3,71,41,7,55,64,5,63,37,41,31,91,61,69,1 %N A141470 Number of 3's in A139067(n). %Y A141470 Cf. A139067. %K A141470 nonn,base %O A141470 1,5 %A A141470 _Paul Curtz_ and _Ray Chandler_, Aug 14 2008