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Length of second run of 1's in binary expansion of n.
3

%I #20 Oct 12 2018 04:41:26

%S 0,0,0,0,0,1,0,0,0,1,1,2,0,1,0,0,0,1,1,2,1,1,2,3,0,1,1,2,0,1,0,0,0,1,

%T 1,2,1,1,2,3,1,1,1,1,2,2,3,4,0,1,1,2,1,1,2,3,0,1,1,2,0,1,0,0,0,1,1,2,

%U 1,1,2,3,1,1,1,1,2,2,3,4,1,1,1,1,1,1,1,1,2,2,2,2,3,3,4,5,0,1,1,2,1

%N Length of second run of 1's in binary expansion of n.

%H Michael De Vlieger, <a href="/A279210/b279210.txt">Table of n, a(n) for n = 0..10000</a>

%F a(2*n) = a(n). - _David A. Corneth_, Oct 12 2018

%e 46 = 101110_2 so a(46) = 3.

%t Table[First[Map[Length, Rest@ DeleteCases[#, w_ /; First@ w == 0] &@ Split@ IntegerDigits[n, 2]] /. {} -> {0}], {n, 100}] (* _Michael De Vlieger_, Dec 23 2016 *)

%Y Cf. A090996, A279209.

%K nonn,base

%O 0,12

%A _N. J. A. Sloane_, Dec 22 2016

%E More terms from _Michael De Vlieger_, Dec 23 2016