A027698 Numbers k such that the k-th prime has an odd number of 1's in its binary expansion.

1, 4, 5, 6, 8, 11, 12, 13, 15, 17, 18, 19, 21, 22, 25, 27, 28, 29, 31, 32, 33, 36, 37, 39, 40, 41, 42, 43, 44, 46, 47, 48, 49, 50, 51, 52, 53, 54, 58, 61, 63, 65, 67, 73, 75, 78, 80, 81, 82, 83, 84, 85, 86, 88, 90, 93, 94, 95, 98, 100, 102, 103, 104, 106, 107, 110, 111, 112

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, A027699, A027700.

Programs

Mathematica

Select[ Range[ 150 ], OddQ[ Length[ Cases[ IntegerDigits[ Prime[ # ], 2 ], 1 ] ] ]& ]
Select[Range[200],OddQ[DigitCount[Prime[#],2,1]]&] (* Harvey P. Dale, Sep 19 2021 *)

Extensions

More terms from Erich Friedman