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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A019288 Let sigma_m (n) be result of applying sum-of-divisors function m times to n; call n (m,k)-perfect if sigma_m (n) = k*n; sequence gives the (2,11)-perfect numbers. 0
4404480, 57669920, 238608384 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See also the Cohen-te Riele links under A019276.

No other terms < 5x10^11. - Jud McCranie, Feb 08 2012

LINKS

Table of n, a(n) for n=1..3.

Graeme L. Cohen and Herman J. J. te Riele, Iterating the sum-of-divisors function, Experimental Mathematics, 5 (1996), pp. 93-100.

CROSSREFS

Sequence in context: A276323 A288086 A210297 * A237910 A244575 A105649

Adjacent sequences:  A019285 A019286 A019287 * A019289 A019290 A019291

KEYWORD

nonn,bref

AUTHOR

N. J. A. Sloane.

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 July 15 14:07 EDT 2019. Contains 325030 sequences. (Running on oeis4.)