login
The OEIS is supported by the many generous donors to the OEIS Foundation.
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A020489
Numbers k such that phi(k) divides sigma_0(k).
0
1, 2, 3, 6, 8, 10, 18, 24, 30
(list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Table of n, a(n) for n=1..9.
MATHEMATICA
Select[Range[30], Divisible[DivisorSigma[0, #], EulerPhi[#]] &] (* Amiram Eldar, May 15 2024 *)
CROSSREFS
Cf. A000005 (sigma_0), A000010 (phi).
Sequence in context: A082667 A098162 A076627 * A002240 A099798 A230108
Adjacent sequences: A020486 A020487 A020488 * A020490 A020491 A020492
KEYWORD
nonn,fini,full
AUTHOR
David W. Wilson
STATUS
approved

Lookup Welcome Wiki Register Music Plot 2 Demos Index WebCam Contribute Format Style Sheet Transforms Superseeker Recents
The OEIS Community
Maintained by The OEIS Foundation Inc.
Last modified September 30 07:15 EDT 2024. Contains 376325 sequences.
License Agreements, Terms of Use, Privacy Policy