|
| |
|
|
A030164
|
|
Numbers n such that uphi(sigma(n))=n, where the unitary phi function (A047994) is defined by: if x=p1^r1*p2^r2*p3^r3*... then uphi(x)=(p1^r1-1)(p2^r2-1)(p3^r3-1)...
|
|
0
| |
|
|
1, 2, 3, 6, 7, 8, 14, 24, 31, 56, 62, 127, 128, 248, 254, 384, 720, 896, 1016, 3968, 8191, 16256, 16382, 32768, 65528, 98304, 103680, 131071, 229376, 262142, 524287
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Fixed points of the function UnitaryPhi(sigma(n)) = 1, 2, 3, 6, 2, 6, 7, 8, 12, 8, 6, 18, 6, 14, 14, 30, 8, 24, 12,.. (Note that this list of numbers contains UnitaryPhi(sigma(n)), n>=1, not the fixed points a(n)).
Contains also 50181120 and 2147483648.
|
|
|
CROSSREFS
| Sequence in context: A189013 A127330 A035346 * A066646 A110920 A145266
Adjacent sequences: A030161 A030162 A030163 * A030165 A030166 A030167
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp)
|
| |
|
|
