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 A161398 #11 Mar 11 2014 01:32:32 %S A161398 1,1,3,1,5,3,7,1,3,5,11,3,13,7,15,1,17,3,19,5,7,11,23,3,25,13,27,7,29, %T A161398 15,31,1,3,17,7,3,37,19,39,5,41,7,43,11,15,23,47,3,7,25,51,13,53,27, %U A161398 55,7,57,29,59,15,61,31,63,1,5,3,67,17,69,7,71,3,73,37,15,19,77,39,79,5,81 %N A161398 a(n) = the smallest divisor of n that contains the same number of 1's as n when both numbers are written in binary. %H A161398 Paul Tek, <a href="/A161398/b161398.txt">Table of n, a(n) for n = 1..10000</a> %Y A161398 Cf. A161399. %K A161398 base,nonn %O A161398 1,3 %A A161398 _Leroy Quet_, Jun 09 2009 %E A161398 More terms from _Sean A. Irvine_, Oct 22 2009