A235331 Numbers with odious squares.

1, 2, 4, 5, 7, 8, 9, 10, 11, 14, 16, 17, 18, 19, 20, 22, 23, 25, 28, 29, 31, 32, 33, 34, 35, 36, 38, 39, 40, 41, 43, 44, 46, 49, 50, 51, 55, 56, 58, 59, 62, 64, 65, 66, 67, 68, 70, 71, 72, 75, 76, 77, 78, 79, 80, 82, 85, 86, 87, 88, 89, 91, 92, 95, 97, 98, 100

Offset

1,2

Comments

Numbers that are sqrt(odious squares).

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..2600

Formula

a(n) = sqrt(A235001(n)).

Example

1 = sqrt(A235001(1)) = sqrt(1).
2 = sqrt(A235001(2)) = sqrt(4).
4 = sqrt(A235001(3)) = sqrt(16).
5 = sqrt(A235001(4)) = sqrt(25).

Mathematica

Select[Range[200], OddQ[DigitCount[#^2, 2][[1]]] &] (* Vincenzo Librandi, Jan 31 2018 *)

Prog

(Magma) [n : n in [0..130] |IsOdd(&+Intseq(n^2, 2))]; // Vincenzo Librandi, Jan 31 2018
(PARI) isok(n) = (hammingweight(n^2) % 2) == 1; \\ Michel Marcus, Jan 31 2018

Crossrefs

Cf. A235001, A194991.

Sequence in context: A039099 A215069 A035257 * A175969 A183573 A187895

Adjacent sequences: A235328 A235329 A235330 * A235332 A235333 A235334

Keyword

nonn,easy

Author

Gerasimov Sergey, Jan 06 2014

Status

approved