A353687 - OEIS

A353687

a(n) = 1 if A098987(n) == 1, otherwise 0.

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

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OFFSET

LINKS

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

Index entries for characteristic functions

MATHEMATICA

Table[Boole[Numerator[DivisorSum[n, (-1)^(# + 1)/# &]] == 1], {n, 1, 120}] (* Amiram Eldar, May 06 2022 *)

PROG

(PARI) A353687(n) = (1==numerator(sumdiv(n, d, ((-1)^(1+d))/d)));

CROSSREFS

Apparently the characteristic function of A069519. Cf. A098987.

Sequence in context: A354188 A342025 A353518 * A354918 A354108 A181101

Adjacent sequences: A353684 A353685 A353686 * A353688 A353689 A353690

KEYWORD

nonn

AUTHOR

Antti Karttunen, May 06 2022

STATUS

approved