|
Search: id:A065528
|
|
|
| A065528 |
|
Numbers n such that phi(n) is expressible as a nontrivial power b^c where b > 1 and c > 1. |
|
+0
2
|
|
| 5, 8, 10, 12, 15, 16, 17, 20, 24, 30, 32, 34, 37, 40, 48, 51, 57, 60, 63, 64, 68, 74, 76, 80, 85, 96, 101, 102, 108, 114, 120, 125, 126, 128, 136, 160, 170, 185, 192, 197, 202, 204, 219, 240, 247, 250, 255, 256, 257, 259, 272, 273, 285, 292, 296, 304, 315, 320, 327, 333
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
What values of b can occur?
phi(n) is a nontrivial power. [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Oct 25 2009]
|
|
FORMULA
|
a(n)=A166955(n+2). [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Oct 25 2009]
|
|
EXAMPLE
|
phi(63) = 6^2, phi(96) = 2^5.
|
|
PROGRAM
|
(PARI) v=[]; for(n=2, 333, if(ispower(eulerphi(n)), v=concat(v, n))); v (Hobson)
|
|
CROSSREFS
|
Cf. A000010.
Cf. A001597, A166955. [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Oct 25 2009]
Sequence in context: A064362 A115401 A153663 this_sequence A050936 A084146 A087280
Adjacent sequences: A065525 A065526 A065527 this_sequence A065529 A065530 A065531
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Nov 27 2001
|
|
EXTENSIONS
|
More terms from Nick Hobson Nov 29 2006
|
|
|
Search completed in 0.002 seconds
|
