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 A279209 #16 Feb 15 2017 09:41:32
%S A279209 1,0,1,0,2,1,1,0,3,2,1,1,2,1,1,0,4,3,2,2,1,1,1,1,3,2,1,1,2,1,1,0,5,4,
%T A279209 3,3,2,2,2,2,1,1,1,1,1,1,1,1,4,3,2,2,1,1,1,1,3,2,1,1,2,1,1,0,6,5,4,4,
%U A279209 3,3,3,3,2,2,2,2,2,2,2,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1
%N A279209 Length of first run of 0's in binary expansion of n.
%H A279209 Vincenzo Librandi, <a href="/A279209/b279209.txt">Table of n, a(n) for n = 0..10000</a>
%e A279209 4 = 100_2 so a(4) = 2.
%t A279209 Table[First[Map[Length, DeleteCases[Split@IntegerDigits[n, 2], w_/;Times@@w>0]]/.{}->{0}], {n, 0, 200}] (* _Vincenzo Librandi_, Dec 23 2016 *) (* after _Michael De Vlieger_ *)
%Y A279209 Cf. A090996, A279210.
%K A279209 nonn,base
%O A279209 0,5
%A A279209 _N. J. A. Sloane_, Dec 22 2016