|
| |
|
|
A050472
|
|
Numbers n such that 2*phi(n) = phi(n+1).
|
|
7
| |
|
|
2, 4, 16, 154, 256, 286, 364, 804, 1066, 2146, 3382, 4550, 6106, 7700, 8176, 9268, 11284, 12556, 12970, 16402, 19228, 19276, 20272, 25132, 26404, 27346, 29154, 29574, 35644, 36418, 38368, 39646, 40494, 47214, 52234, 54652, 65536, 84862
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
REFERENCES
| R. K. Guy, Unsolved Problems Number Theory, Sect. B36.
|
|
|
LINKS
| Donovan Johnson, Table of n, a(n) for n = 1..1000
|
|
|
FORMULA
| Conjecture : a(n)/n^3 is bounded. Does lim n -> infinity a(n)/n^3 = 2 ? - Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 07 2002
|
|
|
EXAMPLE
| phi(256)=128, phi(256+1)=2*128, so 256 is a member of the sequence.
|
|
|
CROSSREFS
| Cf. A000010, A001274, A050473.
Sequence in context: A073924 A061588 A202360 * A109457 A105788 A071008
Adjacent sequences: A050469 A050470 A050471 * A050473 A050474 A050475
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Jud McCranie (JudMcCranie(AT)ugaalum.uga.edu), Dec 24 1999
|
| |
|
|
