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%I #14 Apr 13 2021 23:08:57
%S 2,4,5,6,8,9,11,12,13,14,16,17,19,23,24,25,27,28,29,30,32,33,35,39,47,
%T 48,49,51,55,56,57,59,60,61,62,64,65,67,71,79,95,96,97,99,103,111,112,
%U 113,115,119,120,121,123,124,125,126,128,129
%N a(n) = (s(n)-1)/2, where s(n) is the n-th number whose base-2 representation has exactly 3 runs.
%C a(n) = A238246(n) - 1. - _Reinhard Zumkeller_, Feb 20 2014
%H Vincenzo Librandi, <a href="/A043687/b043687.txt">Table of n, a(n) for n = 1..1000</a>
%t (# - 1)/2&/@Select[Range[1000], Length[Split[IntegerDigits[#, 2]]]==3&] (* _Vincenzo Librandi_, Feb 22 2014 *)
%Y Cf. A238246.
%K nonn,base
%O 1,1
%A _Clark Kimberling_
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