A218428 - OEIS

A218428

Numbers k for which sigma(k)/k - 1/7 is an integer.

7, 56, 3724, 333312, 939466752, 88884432000, 95088913920, 183694492800, 85621850496000, 120354474240000, 176951824358400, 239555577824640, 268015772344320, 2056513874688000, 9918742759833600, 93442741956748800, 149180517860774400, 230762478968017920

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OFFSET

1,1

COMMENTS

a(8) > 10^11. - Donovan Johnson, Oct 31 2012

a(9) > 10^12. - Giovanni Resta, Nov 04 2012

Note that there are no terms here with abundancy 29/7. - Michel Marcus, Jun 25 2013

LINKS

Table of n, a(n) for n=1..18.

CROSSREFS

Cf. A218409, A218410, A218411, A218412, A218413.

Sequence in context: A245249 A110830 A304691 * A365102 A274721 A180817

Adjacent sequences: A218425 A218426 A218427 * A218429 A218430 A218431

KEYWORD

nonn

AUTHOR

Zdenek Cervenka, Oct 28 2012

EXTENSIONS

a(5)-a(7) from Donovan Johnson, Oct 31 2012

a(8) from Giovanni Resta, Nov 04 2012

More terms from Michel Marcus, Jun 25 2013

STATUS

approved