A353569 a(n) = 1 if n is an odd number divisible by a square > 1, otherwise 0.

0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions.

Formula

a(n) = A000035(n) * A107078(n).

a(n) = A000035(n) - A323239(n).

a(n) <= A353626(n).

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 1/2 - 4/Pi^2 = 0.094715... . - Amiram Eldar, Jul 24 2022

Mathematica

a[n_] := If[OddQ[n] && !SquareFreeQ[n], 1, 0]; Array[a, 100] (* Amiram Eldar, Jul 24 2022 *)

Prog

(PARI) A353569(n) = ((n%2)&&!issquarefree(n));

Crossrefs

Characteristic function of A053850.

Cf. A000035, A107078, A323239, A353626.

Sequence in context: A369640 A037816 A353639 * A353477 A044939 A373973

Adjacent sequences: A353566 A353567 A353568 * A353570 A353571 A353572

Keyword

nonn

Author

Antti Karttunen, May 03 2022

Extensions

Definition clarified by Antti Karttunen, Feb 19 2023

Status

approved