|
Search: id:A075863
|
|
|
| A075863 |
|
phi(phi(n)) = sum of prime factors of n. |
|
+0
1
|
|
| 8, 45, 55, 95, 126, 132, 198, 215, 228, 516, 2855, 6852, 7655, 18372
(list; graph; listen)
|
|
|
OFFSET
|
2,1
|
|
|
EXAMPLE
|
phi(phi(126)) = phi(36) = 12 and the sum of the prime factors of 126 = 2 * 3^2 * 7 is 2 + 3 + 7 = 12. Hence 126 belongs to the sequence.
|
|
MATHEMATICA
|
Select[Range[2, 10^5], EulerPhi[EulerPhi[ # ]] == Apply[Plus, Transpose[FactorInteger[ # ]][[1]]] &]
|
|
CROSSREFS
|
Sequence in context: A001689 A028565 A129553 this_sequence A118838 A153828 A100648
Adjacent sequences: A075860 A075861 A075862 this_sequence A075864 A075865 A075866
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Oct 15 2002
|
|
|
Search completed in 0.002 seconds
|
