A325964 a(n) = 1 if n and sigma(n) are relatively prime, 0 otherwise, where sigma(n) = sum of divisors of n, A000203; Characteristic function of A014567.

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

Offset

1

Links

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

Index entries for characteristic functions

Index entries for sequences related to sigma(n)

Formula

a(n) = 1 if gcd(n, sigma(n)) [= A009194(n)] is 1, 0 otherwise.

Mathematica

A325964[n_] := Boole[CoprimeQ[n, DivisorSigma[1, n]]];
Array[A325964, 100] (* Paolo Xausa, Oct 11 2025 *)

Prog

(PARI) A325964(n) = (1==gcd(n, sigma(n)));

Crossrefs

Cf. A000203, A009194, A014567.

Cf. also A297086, A322980.

Sequence in context: A340375 A010055 A324290 * A344885 A345064 A076699

Adjacent sequences: A325961 A325962 A325963 * A325965 A325966 A325967

Keyword

nonn,easy

Author

Antti Karttunen, May 29 2019

Status

approved