cp's OEIS Frontend

A059012 Numbers that have an even number of 0's and 1's in their binary expansion.

%I A059012 #23 Aug 16 2021 13:43:28
%S A059012 3,9,10,12,15,33,34,36,39,40,43,45,46,48,51,53,54,57,58,60,63,129,130,
%T A059012 132,135,136,139,141,142,144,147,149,150,153,154,156,159,160,163,165,
%U A059012 166,169,170,172,175,177,178,180,183,184,187,189,190,192,195,197,198
%N A059012 Numbers that have an even number of 0's and 1's in their binary expansion.
%C A059012 Intersection of A001969 and A059010.
%H A059012 Indranil Ghosh, <a href="/A059012/b059012.txt">Table of n, a(n) for n = 1..32768</a>
%e A059012 36 is in the sequence because 36 = 100100_10. '100100' has two 1's and four 0's. - _Indranil Ghosh_, Feb 10 2017
%t A059012 Select[Range[200],AllTrue[{DigitCount[#,2,0],DigitCount[#,2,1]},EvenQ]&] (* _Harvey P. Dale_, Aug 16 2021 *)
%o A059012 (PARI) is(n)=hammingweight(n)%2==0 && hammingweight(bitneg(n, #binary(n)))%2==0 \\ _Charles R Greathouse IV_, Mar 26 2013
%o A059012 (Python)
%o A059012 i=0
%o A059012 j=1
%o A059012 while j<=300:
%o A059012     if bin(i)[2:].count("1")%2 == 0 == bin(i)[2:].count("0")%2:
%o A059012         print(str(j)+" "+str(i))
%o A059012         j+=1
%o A059012     i+=1 # _Indranil Ghosh_, Feb 10 2017
%Y A059012 Cf. A000069, A001969, A059009-A059014.
%K A059012 nonn,base,easy
%O A059012 1,1
%A A059012 _Patrick De Geest_, Dec 15 2000