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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A153800 Indices of perfect numbers (A000396) in the sequence of multiply-perfect numbers (A007691). 5
2, 3, 5, 7, 13, 19, 25, 41, 110, 192, 229, 294 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence contains no further entries between 294 and 1600. - R. J. Mathar, May 26 2011

LINKS

Table of n, a(n) for n=1..12.

EXAMPLE

a(7) is 25 because the 25th multiply-perfect number A007691(25)=137438691328 is also the 7th perfect number A000396(7).

CROSSREFS

Cf. A000396, A007691.

Sequence in context: A233043 A231099 A062252 * A147791 A169647 A072467

Adjacent sequences:  A153797 A153798 A153799 * A153801 A153802 A153803

KEYWORD

more,nonn

AUTHOR

Omar E. Pol, Jan 13 2009

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 December 15 11:43 EST 2019. Contains 329999 sequences. (Running on oeis4.)