A091258 - OEIS

A091258

Denominator of sigma_3(n)/sigma(n).

1, 1, 1, 7, 1, 1, 1, 1, 13, 1, 1, 1, 1, 1, 1, 1, 1, 13, 1, 1, 1, 1, 1, 1, 31, 1, 1, 7, 1, 1, 1, 7, 1, 1, 1, 91, 1, 1, 1, 1, 1, 1, 1, 7, 13, 1, 1, 1, 19, 31, 1, 7, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 31, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13, 1, 7, 1, 1, 1, 1, 1, 19, 13

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OFFSET

1,4

COMMENTS

Conjecture: The set of distinct terms is A004611. - Michel Marcus, Aug 10 2024

LINKS

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

MATHEMATICA

Denominator[Table[DivisorSigma[3, n]/DivisorSigma[1, n], {n, 100}]] (* Harvey P. Dale, Oct 06 2017 *)

PROG

(PARI) a(n) = denominator(sigma(n, 3)/sigma(n)); \\ Michel Marcus, Dec 29 2013

CROSSREFS