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A091259 Numerator of sigma_3(n)/sigma(n). 4
1, 3, 7, 73, 21, 21, 43, 39, 757, 63, 111, 73, 157, 129, 147, 151, 273, 2271, 343, 219, 301, 333, 507, 273, 15751, 471, 511, 3139, 813, 441, 931, 4161, 777, 819, 903, 55261, 1333, 1029, 1099, 819, 1641, 903, 1807, 8103, 15897, 1521, 2163, 1057, 39331, 47253 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

If n is prime then a(n) = A002061(n). - Robert Israel, Jan 25 2018

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

seq(numer(numtheory:-sigma[3](n)/numtheory:-sigma(n)), n=1..100); # Robert Israel, Jan 25 2018

MATHEMATICA

Array[Numerator[DivisorSigma[3, #]/DivisorSigma[1, #]]&, 50] (* Harvey P. Dale, Feb 29 2016 *)

PROG

(PARI) a(n) = numerator(sigma(n, 3)/sigma(n)); \\ Michel Marcus, Jan 26 2018

(MAGMA) [Numerator(DivisorSigma(3, n)/DivisorSigma(1, n)): n in [1..50]]; // Vincenzo Librandi, Jan 26 2018

CROSSREFS

Cf. A001158, A000203, A002061, A091258, A091260.

Sequence in context: A209477 A209336 A078552 * A354891 A354893 A342546

Adjacent sequences:  A091256 A091257 A091258 * A091260 A091261 A091262

KEYWORD

easy,nonn,frac,look

AUTHOR

Labos Elemer, Feb 12 2004

STATUS

approved

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Last modified June 25 10:04 EDT 2022. Contains 354844 sequences. (Running on oeis4.)