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A077089 Quotients when sigma(n+1)/sigma(n) is integer. 1
3, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 3, 1, 3, 1, 2, 1, 2, 2, 3, 2, 1, 1, 1, 1, 1, 3, 1, 1, 1, 2, 2, 2, 2, 3, 1, 2, 2, 3, 2, 2, 1, 2, 1, 2, 1, 1, 1, 1, 2, 3, 2, 2, 1, 2, 2, 1, 2, 3, 3, 1, 3, 1, 2, 2, 2, 3, 2, 1, 1, 3, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 1, 3, 3, 2, 1, 2, 1, 2, 2, 3, 1, 2, 2, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..500

FORMULA

a(n) = sigma(A058072(n)+1)/sigma(A058072(n)). - Seiichi Manyama, Jan 16 2021

EXAMPLE

a(1) = sigma(2)/sigma(1) = 3/1 = 3.

a(2) = sigma(6)/sigma(5) = 12/6 = 2.

a(3) = sigma(15)/sigma(14) = 24/24 = 1.

MATHEMATICA

Do[s=Mod[a=DivisorSigma[1, n+1], b=DivisorSigma[1, n]]; If[Equal[s, 0], Print[a/b]], {n, 1, 10000000}]

Select[#[[2]]/#[[1]]&/@Partition[DivisorSigma[1, Range[10^6]], 2, 1], IntegerQ] (* Harvey P. Dale, Dec 26 2015 *)

CROSSREFS

Cf. A000203, A002961, A058072, A067081, A077086, A077087.

Sequence in context: A306287 A016457 A181715 * A156352 A175191 A328928

Adjacent sequences:  A077086 A077087 A077088 * A077090 A077091 A077092

KEYWORD

nonn

AUTHOR

Labos Elemer, Oct 31 2002

STATUS

approved

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Last modified September 20 14:44 EDT 2021. Contains 347586 sequences. (Running on oeis4.)