A323152 a(n) = 1 if sigma(n) is divisible by all proper divisors of n, 0 otherwise.

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

Offset

1

Comments

Characteristic function of A166070.

Differs from A323153 at positions n = 1, 120, 672, 30240, 32760, ...

Links

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

Index entries for characteristic functions

Mathematica

Table[If[AllTrue[DivisorSigma[1, n]/Most[Divisors[n]], IntegerQ], 1, 0], {n, 150}] (* Harvey P. Dale, Mar 06 2023 *)

Prog

(PARI) A323152(n) = { my(s=sigma(n)); fordiv(n, d, if((d<n)&&(s%d), return(0))); (1); };

Crossrefs

Cf. A166070, A323153.

Sequence in context: A188318 A361897 A189206 * A192280 A342005 A354355

Adjacent sequences: A323149 A323150 A323151 * A323153 A323154 A323155

Keyword

nonn

Author

Antti Karttunen, Jan 09 2019

Status

approved