A380440 a(n) = 1 if n has no squarefree divisor d such that d^2 > n, otherwise 0.

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

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Index entries for characteristic functions.

Mathematica

A380440[n_] := Boole[Select[Divisors[n], #^2 > n && SquareFreeQ[#] &] == {}];
Array[A380440, 100] (* Paolo Xausa, Jan 27 2025 *)

Prog

(PARI) A380440(n) = { fordiv(n, d, if((d^2)>n && issquarefree(d), return(0))); (1); };

Crossrefs

Characteristic function of A341645, numbers without a strictly superior squarefree divisor.

Cf. A005117.

Sequence in context: A307423 A355684 A355683 * A373374 A120523 A269625

Adjacent sequences: A380437 A380438 A380439 * A380441 A380442 A380443

Keyword

nonn

Author

Antti Karttunen, Jan 27 2025

Status

approved