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A218406 Numbers n for which sigma(n)/n = k+1/5 with integer k. 3
5, 420, 7440, 8190, 18600, 121920, 131040, 95472000, 102136320, 197308800, 433305600, 503255040, 71271827200, 91967616000, 128848035840, 190066406400, 287879454720, 354560976000, 799959888000, 2061580369920, 2208930048000, 100368143884800, 341546502528000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(15) > 10^11. - Donovan Johnson, Oct 31 2012

a(20) > 10^12. - Giovanni Resta, Nov 04 2012

Note that there are no terms here with abundancy 11/5 (k=2). - Michel Marcus, Jun 26 2013

LINKS

Table of n, a(n) for n=1..23.

FORMULA

sigma(n)/n = k+1/5 with integer k.

CROSSREFS

Cf. A218407, A218408, A218427.

Sequence in context: A216089 A201887 A301309 * A217939 A147684 A199090

Adjacent sequences:  A218403 A218404 A218405 * A218407 A218408 A218409

KEYWORD

nonn

AUTHOR

Zdenek Cervenka, Oct 28 2012

EXTENSIONS

a(8)-a(14) from Donovan Johnson, Oct 31 2012

a(15)-a(19) from Giovanni Resta, Nov 04 2012

More terms from Michel Marcus, Jun 26 2013

STATUS

approved

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Last modified February 20 06:26 EST 2019. Contains 320332 sequences. (Running on oeis4.)