A365716 a(n) = 1 if the largest divisor of n <= sqrt(n) is a power of 2, otherwise 0.

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

Offset

1

Links

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

Index entries for characteristic functions

Formula

a(n) = A209229(A033676(n)).

a(n) >= A365605(n).

Mathematica

Table[If[IntegerQ[Log2[Max[Select[Divisors[n], #<=Sqrt[n]&]]]], 1, 0], {n, 110}] (* Harvey P. Dale, May 26 2024 *)

Prog

(PARI)
A209229(n) = (n && !bitand(n, n-1));
A033676(n) = { my(d); if(n<2, 1, d=divisors(n); d[(length(d)+1)\2]) }; \\ From A033676.
A365716(n) = A209229(A033676(n));

Crossrefs

Characteristic function of A365406.

Cf. A033676, A209229, A365605.

Sequence in context: A267256 A351824 A365605 * A334460 A071023 A166280

Adjacent sequences: A365713 A365714 A365715 * A365717 A365718 A365719

Keyword

nonn

Author

Antti Karttunen, Oct 22 2023

Status

approved