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 A143909 #8 Sep 16 2015 12:36:39
%S A143909 2,5,6,9,10,11,12,13,14,23,27,29,30,35,37,38,39,41,42,43,44,45,46,47,
%T A143909 49,50,51,52,53,54,55,56,57,58,59,60,61,62,95,111,119,123,125,126,135,
%U A143909 139,141,142,147,149,150,153,154,156,159,163,165,166,169,170,172,175,177
%N A143909 A positive integer n is included if the number of digits in the binary representation of n is a multiple of the number of zeros in the binary representation of n.
%F A143909 {n: A080791(n) | A070939(n)}. - _R. J. Mathar_, Sep 05 2008
%p A143909 A070939 := proc(n) max(1,1+floor(ilog2(n))) ; end: A080791 := proc(n) local dgs ; dgs := convert(n,base,2) ; nops(dgs)-add(i,i=dgs) ; end: isA143909 := proc(n) zs := A080791(n) ; if zs > 0 then if A070939(n) mod zs = 0 then true ; else false ; fi; else false ; fi; end: for n from 1 to 500 do if isA143909(n) then printf("%d,",n) ; fi; od: # _R. J. Mathar_, Sep 05 2008
%t A143909 Select[Range[200], DigitCount[ #, 2, 0] > 0 && Mod[Length[IntegerDigits[ #, 2]], DigitCount[ #, 2, 0]] == 0 &] (* _Stefan Steinerberger_, Sep 05 2008 *)
%Y A143909 Cf. A096199.
%K A143909 base,nonn
%O A143909 1,1
%A A143909 _Leroy Quet_, Sep 04 2008
%E A143909 More terms from _Stefan Steinerberger_ and _R. J. Mathar_, Sep 05 2008