|
| |
|
|
A109889
|
|
Numbers n such that 3^n - phi(n) is prime.
|
|
0
|
|
|
|
1, 4, 5, 6, 20, 22, 25, 46, 47, 214, 822, 985, 3273, 3590, 4658, 4768, 17250, 38697
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
COMMENTS
|
Terms less than 1000 correspond to certified primes. Next term is greater than 10000.
a(19) > 10^5. [From Donovan Johnson, Feb 06 2010]
|
|
|
LINKS
|
Table of n, a(n) for n=1..18.
|
|
|
MATHEMATICA
|
Do[If[PrimeQ[3^n - EulerPhi[n]], Print[n]], {n, 1, 10^4}]
|
|
|
CROSSREFS
|
Sequence in context: A010753 A221174 A047195 * A103518 A103313 A036492
Adjacent sequences: A109886 A109887 A109888 * A109890 A109891 A109892
|
|
|
KEYWORD
|
hard,nonn
|
|
|
AUTHOR
|
Ryan Propper, Aug 31 2005
|
|
|
EXTENSIONS
|
a(17)-a(18) from Donovan Johnson, Feb 06 2010
|
|
|
STATUS
|
approved
|
| |
|
|
