OFFSET
1,2
LINKS
Peter J. C. Moses, Table of n, a(n) for n = 1..10000
MAPLE
select(t -> convert(convert(3^t, base, 2), `+`)::odd, [$0..200]); # Robert Israel, Oct 10 2016
MATHEMATICA
Select[Range[0, 200], OddQ[DigitCount[3^#, 2][[1]]]&] (* Peter J. C. Moses, Mar 30 2013 *)
PROG
(PARI) isok(n) = (hammingweight(3^n) % 2) == 1; \\ Michel Marcus, Oct 11 2016
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Vladimir Shevelev, Mar 29 2013
STATUS
approved