login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A066930 Numbers n such that phi(sigma(n)) divides sigma(phi(n)). 2
1, 7, 9, 29, 71, 97, 109, 121, 139, 142, 175, 183, 194, 215, 225, 242, 244, 261, 278, 311, 344, 349, 355, 430, 497, 509, 516, 533, 556, 571, 605, 622, 631, 647, 673, 709, 729, 791, 817, 859, 911, 923, 1021, 1066, 1112, 1119, 1142, 1207, 1243, 1262, 1277 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

PROG

(PARI) { n=0; for (m=1, 10^10, if (sigma(eulerphi(m)) % eulerphi(sigma(m)) == 0, write("b066930.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Apr 08 2010

CROSSREFS

Cf. A033632.

Sequence in context: A030404 A242505 A263826 * A247192 A154260 A309199

Adjacent sequences:  A066927 A066928 A066929 * A066931 A066932 A066933

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Jan 26 2002

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 June 15 22:06 EDT 2021. Contains 345053 sequences. (Running on oeis4.)