A298879 - OEIS

A298879

Numbers whose square is not odious.

0, 3, 6, 12, 13, 15, 21, 24, 26, 27, 30, 37, 42, 45, 47, 48, 52, 53, 54, 57, 60, 61, 63, 69, 73, 74, 81, 83, 84, 90, 93, 94, 96, 99, 104, 105, 106, 107, 108, 109, 111, 114, 115, 119, 120, 122, 123, 126, 133, 137, 138, 141, 146, 148, 151, 155, 159

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Complement of A235331.

From Robert Israel, Feb 02 2018: (Start)

2*n is in the sequence if and only if n is in the sequence.

2*n+1 is in the sequence if and only if n*(n+1) is odious. (End)

LINKS

Table of n, a(n) for n=1..57.

MAPLE

select(t -> convert(convert(t^2, base, 2), `+`)::even, [$0..200]); # Robert Israel, Feb 02 2018

MATHEMATICA

Join[{0}, Select[Range[200], !OddQ[DigitCount[#^2, 2][[1]]] &]]

PROG

(Magma) [n: n in [0..200] | IsEven(&+Intseq(n^2, 2))];

(PARI) isok(n) = (hammingweight(n^2) % 2) != 1; \\ Michel Marcus, Jan 31 2018

CROSSREFS

Cf. A235001, A235331.

Sequence in context: A090553 A078502 A107974 * A116625 A287560 A318934

Adjacent sequences: A298876 A298877 A298878 * A298880 A298881 A298882

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Jan 31 2018

STATUS

approved