A235336 Numbers having evil number of 1's in their binary representation.

0, 7, 11, 13, 14, 19, 21, 22, 25, 26, 28, 31, 35, 37, 38, 41, 42, 44, 47, 49, 50, 52, 55, 56, 59, 61, 62, 63, 67, 69, 70, 73, 74, 76, 79, 81, 82, 84, 87, 88, 91, 93, 94, 95, 97, 98, 100, 103, 104, 107, 109, 110, 111, 112, 115, 117, 118, 119, 121, 122, 123, 124, 125, 126, 131

Offset: 0

Author

Vladimir Shevelev, Jan 06 2014

Keywords

• nonn
• base

Comments

A000120(a(n)) is in A001969.

Except for 0, the first term in which the sequence differs from A075930 is the 27th: a(27) = 63.

Also a(27) = 63 is the first odd term that is not in A092246. - Altug Alkan, Mar 18 2018

Examples

			7 in binary has 3 1's and since 3 is evil (i.e., belongs to A001969), then 7 is in the sequence.
		

Links

• Robert Israel, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A000120, A001969, A075930, A092246.

Programs

Maple

filter:= n ->
  convert(convert(convert(convert(n,base,2),`+`),base,2),`+`)::even:
select(filter, [$0..131]); # Robert Israel, Mar 18 2018

Mathematica

Select[Range[0, 150], EvenQ[DigitCount[DigitCount[#, 2, 1], 2, 1]] &] (* Amiram Eldar, Jul 24 2023 *)