A373993 a(n) = 1 if the number of divisors of n divides n-1, otherwise 0.

1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 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..100000

Index entries for characteristic functions

Mathematica

A373993[n_] := Boole[Divisible[n - 1, DivisorSigma[0, n]]];
Array[A373993, 100] (* Paolo Xausa, Jun 30 2024 *)

Prog

(PARI) A373993(n) = !((n-1)%numdiv(n));

Crossrefs

Characteristic function of A354711.

Cf. A000005.

Sequence in context: A120530 A078616 A267800 * A322980 A267053 A359591

Adjacent sequences: A373990 A373991 A373992 * A373994 A373995 A373996

Keyword

nonn

Author

Antti Karttunen, Jun 30 2024

Status

approved