login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A218413 Numbers n for which sigma(n)/n = k+6/7 with integer k. 5
168, 11172, 217854, 228480, 446880, 220093440, 5228496000, 10805558400, 14091504577920, 583455456460800, 2583890834482298880, 5510058011880428160, 224050000769667072000, 1022756201136515973120, 1314073124731389718080, 2661277331943365990400 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(9) > 10^11. - Donovan Johnson, Oct 31 2012

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

Note that there are no terms with abundancy 13/7. - Michel Marcus, Jun 25 2013

LINKS

Table of n, a(n) for n=1..16.

FORMULA

sigma(n)/n = k+6/7 with integer k.

CROSSREFS

Cf. A218428, A218409, A218410, A218411, A218412.

Sequence in context: A006363 A271033 A019286 * A064767 A115222 A290152

Adjacent sequences:  A218410 A218411 A218412 * A218414 A218415 A218416

KEYWORD

nonn

AUTHOR

Zdenek Cervenka, Oct 28 2012

EXTENSIONS

a(6)-a(8) from Donovan Johnson, Oct 31 2012

More terms from Michel Marcus, Jun 25 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 24 23:01 EDT 2019. Contains 326314 sequences. (Running on oeis4.)