A091785 - OEIS

%I #28 Jan 21 2020 21:04:10

%S 3,5,9,12,15,17,20,23,27,29,33,36,39,43,45,48,51,53,57,60,63,65,68,71,

%T 75,77,80,83,85,89,92,95,99,101,105,108,111,113,116,119,123,125,129,

%U 132,135,139,141,144,147,149,153,156,159,163,165,169,172,175,177,180,183

%N Evil numbers (see A001969) in A003159.

%C Also n such that A033485(n) == 3 (mod 4); see A007413.

%C Also n such that A029883(n-1) = -1, A036577(n-1) = 0, A036585(n-1) = 1. - _Philippe Deléham_, Mar 25 2004

%C The number of odd numbers before the n-th even number in this sequence is a(n). - _Philippe Deléham_, Mar 27 2004

%C Numbers n such that {A010060(n-1), A010060(n)}={1,0} where A010060 is the Thue-Morse sequence. - _Benoit Cloitre_, Jun 16 2006

%H G. C. Greubel, <a href="/A091785/b091785.txt">Table of n, a(n) for n = 1..10000</a>

%H Aviezri S. Fraenkel, <a href="http://www.wisdom.weizmann.ac.il/~fraenkel/Papers/DISC8773.pdf">The vile, dopey, evil and odious game players</a>, Discrete Math. 312 (2012), pp. 42-46.

%H <a href="/index/Ar#2-automatic">Index entries for 2-automatic sequences</a>.

%F a(n) = A003159(2*n) = A036554(2*n)/2.

%F a(n) is asymptotic to 3*n. - _Benoit Cloitre_, Mar 22 2004

%F A050292(a(n)) = 2n. - _Philippe Deléham_, Mar 26 2004

%t A036554 := Select[Range[750], OddQ[IntegerExponent[#, 2]] &]; Table[ A036554[[2*n]]/2, {n, 1, 50}] (* _G. C. Greubel_, Jan 14 2018 *)

%o (PARI) is(n)=hammingweight(n-1)%2 && hammingweight(n)%2==0 \\ _Charles R Greathouse IV_, Mar 26 2013

%K easy,nonn

%O 1,1

%A _Philippe Deléham_, Mar 16 2004

%E More terms from _Benoit Cloitre_, Mar 22 2004