A218410 - OEIS

A218410

Numbers k for which sigma(k)/k - 3/7 is an integer.

840, 55860, 1089270, 3666432, 5322240, 8714160, 10281600, 20109600, 21785400, 32104800, 9904204800, 10334134272, 4660073935104, 7322605472000, 11887123248000, 15387946358400, 78599399424000, 516876560449536, 750304684523520, 812193794048000

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OFFSET

1,1

COMMENTS

a(13) > 10^11. - Donovan Johnson, Oct 31 2012

a(13) > 10^12. - Giovanni Resta, Nov 04 2012

Note that there are no terms with abundancy 10/7 or 17/7. - Michel Marcus, Jun 25 2013

LINKS

Table of n, a(n) for n=1..20.

CROSSREFS

Cf. A218428, A218409, A218411, A218412, A218413.

Sequence in context: A188781 A166764 A226268 * A022052 A055353 A107516

Adjacent sequences: A218407 A218408 A218409 * A218411 A218412 A218413

KEYWORD

nonn

AUTHOR

Zdenek Cervenka, Oct 28 2012

EXTENSIONS

a(5)-a(12) from Donovan Johnson, Oct 31 2012

More terms from Michel Marcus, Jun 25 2013

STATUS

approved