|
Search: id:A067384
|
|
|
| A067384 |
|
Numbers n such that sigma(phi(n))/sigma(n) = 4. |
|
+0
5
|
|
| 121679, 1043909, 2350171, 2918263, 3396103, 3566807, 3688067, 4019467, 4562827, 5963407, 7300697, 7485979, 7853933, 8103301, 8364151, 9237779, 9514213, 9638527, 10531123, 11094619, 11384447, 12721937, 13576267
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Subset of A066881. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 30 2008]
|
|
MATHEMATICA
|
For[ n=1, True, n++, If[ DivisorSigma[ 1, EulerPhi[ n ] ]/DivisorSigma[ 1, n ]==4, Print[ n ] ] ]
|
|
CROSSREFS
|
Cf. A033631, A066831, A067382, A067383, A067385.
Sequence in context: A061128 A068136 A135495 this_sequence A066881 A048903 A115545
Adjacent sequences: A067381 A067382 A067383 this_sequence A067385 A067386 A067387
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Dean Hickerson (dean.hickerson(AT)yahoo.com), Jan 20 2002
|
|
|
Search completed in 0.002 seconds
|
