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 A161761 #3 Mar 30 2012 18:52:33 %S A161761 11,10101,111010001,1111101000001,1111111111101000000000001, %T A161761 111111111111111010000000000000001, %U A161761 1111111111111111101000000000000000001,1111111111111111111111111111101000000000000000000000000000001 %N A161761 Binary representation of A139224(n). %Y A161761 Cf. A000396, A000668, A139224, A061652. %K A161761 nonn,base %O A161761 1,1 %A A161761 _Juri-Stepan Gerasimov_, Jun 18 2009 %E A161761 Keyword:base added by _R. J. Mathar_, May 21 2010