A354037 a(n) = 1 if sigma(n)-n is a multiple of 4, otherwise 0.

1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 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 A010873(A001065(n)) == 0, otherwise 0.

a(n) = [A010873(n) == A105824(n)], where [ ] is the Iverson bracket.

Mathematica

a[n_] := If[Divisible[DivisorSigma[1, n] - n, 4], 1, 0]; Array[a, 100] (* Amiram Eldar, May 16 2022 *)

Prog

(PARI) A354037(n) = (0==((sigma(n)-n)%4));

Crossrefs

Characteristic function of A354038.

Cf. A000203, A001065, A010873, A105824.

Cf. also A354032, A354097.

Sequence in context: A369975 A369001 A361024 * A185118 A240332 A156297

Adjacent sequences: A354034 A354035 A354036 * A354038 A354039 A354040

Keyword

nonn

Author

Antti Karttunen, May 16 2022

Status

approved