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%I #45 Apr 25 2024 06:42:07
%S 0,4,7,10,11,13,15,16,19,20,22,28,29,30,34,36,41,43,46,48,49,50,53,54,
%T 56,62,63,65,66,67,68,69,80,82,83,84,85,86,87,88,89,90,91,92,93,94,95,
%U 97,98,100,101,103,107,108,110,111,113,114,115,117,118,119,120
%N Numbers k such that 3^k is odious (A000069).
%H Peter J. C. Moses, <a href="/A223024/b223024.txt">Table of n, a(n) for n = 1..10000</a>
%p select(t -> convert(convert(3^t,base,2),`+`)::odd, [$0..200]); # _Robert Israel_, Oct 10 2016
%t Select[Range[0,200], OddQ[DigitCount[3^#,2][[1]]]&] (* _Peter J. C. Moses_, Mar 30 2013 *)
%o (PARI) isok(n) = (hammingweight(3^n) % 2) == 1; \\ _Michel Marcus_, Oct 11 2016
%Y Cf. A000069, A001969, A000244, A237545.
%Y Complement of A371970.
%K nonn,base
%O 1,2
%A _Vladimir Shevelev_, Mar 29 2013