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

1, 4, 7, 16, 19, 21, 22, 25, 26, 28, 31, 64, 67, 69, 70, 73, 74, 76, 79, 81, 82, 84, 87, 88, 91, 93, 94, 97, 98, 100, 103, 104, 107, 109, 110, 112, 115, 117, 118, 121, 122, 124, 127, 256, 259, 261, 262, 265, 266, 268, 271, 273, 274, 276, 279, 280, 283, 285, 286

Offset: 1

Author

Patrick De Geest, Dec 15 2000

Keywords

• nonn
• easy

Examples

			21 is in the sequence because 21 = 10101_2. '10101' has two 0's and three 1's. - _Indranil Ghosh_, Feb 06 2017
		

Links

• Indranil Ghosh, Table of n, a(n) for n = 1..50000 (terms 1..1000 from Harvey P. Dale)

Crossrefs

Cf. A000069, A001969, A059009-A059013.

Programs

Mathematica

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 *)

PARI

is(n)=hammingweight(n)%2 && hammingweight(bitneg(n, #binary(n)))%2==0 \\ Charles R Greathouse IV, Mar 26 2013

Python

i=1
j=1
while j<=100:
    if not bin(i)[2:].count("0")%2 and bin(i)[2:].count("1")%2:
        print(str(j)+" "+str(i))
        j+=1
    i+=1 # Indranil Ghosh, Feb 06 2017