A027700 Numbers k such that the k-th prime has an even number of 1's in its binary expansion.

2, 3, 7, 9, 10, 14, 16, 20, 23, 24, 26, 30, 34, 35, 38, 45, 55, 56, 57, 59, 60, 62, 64, 66, 68, 69, 70, 71, 72, 74, 76, 77, 79, 87, 89, 91, 92, 96, 97, 99, 101, 105, 108, 109, 114, 117, 122, 124, 125, 131, 133, 137, 139, 141, 142, 146, 147, 148, 150, 152, 154, 155, 159, 165, 166, 170, 173, 176, 178

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A027697, A027698, A027699.

Programs

Mathematica

Position[Table[If[EvenQ[DigitCount[n,2,1]],1,0],{n,Prime[Range[ 200]]}],1]//Flatten (* Harvey P. Dale, Jul 11 2017 *)

PARI

n=0;forprime(p=2,97,n++;if(hammingweight(p)%2==0,print1(n", "))) \\ Charles R Greathouse IV, Sep 24 2012

Extensions

Extended (and corrected) by Scott Lindhurst (ScottL(AT)alumni.princeton.edu)