|
|
A110196
|
|
Numbers n such that k=2n is the least k such that phi(n+k)=2*phi(k).
|
|
1
|
|
|
1, 13, 23, 97, 113, 131, 199, 227, 491, 859, 929
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
No other n < 10^6. Note that all n>1 are primes.
|
|
LINKS
|
|
|
MATHEMATICA
|
Do[k=1; While[EulerPhi[n+k] != 2*EulerPhi[k], k++ ]; If[k==2n, Print[n]], {n, 5000}]
|
|
CROSSREFS
|
Cf. A050473 (least k such that phi(n+k)=2*phi(k)).
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|