cp's OEIS Frontend

A059014 Numbers that have an even number of 0's and an odd number of 1's in binary expansion.

%I A059014 #19 Apr 11 2021 04:52:15
%S A059014 1,4,7,16,19,21,22,25,26,28,31,64,67,69,70,73,74,76,79,81,82,84,87,88,
%T A059014 91,93,94,97,98,100,103,104,107,109,110,112,115,117,118,121,122,124,
%U A059014 127,256,259,261,262,265,266,268,271,273,274,276,279,280,283,285,286
%N A059014 Numbers that have an even number of 0's and an odd number of 1's in binary expansion.
%H A059014 Indranil Ghosh, <a href="/A059014/b059014.txt">Table of n, a(n) for n = 1..50000</a> (terms 1..1000 from Harvey P. Dale)
%e A059014 21 is in the sequence because 21 = 10101_2. '10101' has two 0's and three 1's. - _Indranil Ghosh_, Feb 06 2017
%t A059014 en0on1Q[n_]:=Module[{idn2=IntegerDigits[n,2]},EvenQ[Count[idn2,0]] && OddQ[Count[idn2,1]]]; Select[Range[300],en0on1Q] (* _Harvey P. Dale_, Nov 08 2013 *)
%o A059014 (PARI) is(n)=hammingweight(n)%2 && hammingweight(bitneg(n, #binary(n)))%2==0 \\ _Charles R Greathouse IV_, Mar 26 2013
%o A059014 (Python)
%o A059014 i=1
%o A059014 j=1
%o A059014 while j<=100:
%o A059014     if not bin(i)[2:].count("0")%2 and bin(i)[2:].count("1")%2:
%o A059014         print(str(j)+" "+str(i))
%o A059014         j+=1
%o A059014     i+=1 # _Indranil Ghosh_, Feb 06 2017
%Y A059014 Cf. A000069, A001969, A059009-A059013.
%K A059014 nonn,easy
%O A059014 1,2
%A A059014 _Patrick De Geest_, Dec 15 2000