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

1,2

Links

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

Example

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

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 *)

Prog

(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

Crossrefs

Cf. A000069, A001969, A059009-A059013.

Sequence in context: A037373 A310928 A018887 * A360800 A255650 A350961

Adjacent sequences: A059011 A059012 A059013 * A059015 A059016 A059017

Keyword

nonn,easy

Author

Patrick De Geest, Dec 15 2000

Status

approved