OFFSET
1,2
COMMENTS
No other n < 10^6. Note that all n>1 are primes.
MATHEMATICA
Do[k=1; While[EulerPhi[n+k] != 2*EulerPhi[k], k++ ]; If[k==2n, Print[n]], {n, 5000}]
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Jul 15 2005
STATUS
approved