OFFSET
1,1
COMMENTS
It is obvious that all terms are primes.
MATHEMATICA
Do[If[n=Prime[m]; m==DivisorSigma[1, EulerPhi[PrimePi[n]]], Print[n]], {m, 235000000}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Farideh Firoozbakht, Aug 04 2009
EXTENSIONS
Formula and six more terms from Max Alekseyev, Jun 25 2011
STATUS
approved