OFFSET
1,1
COMMENTS
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[200], PrimeQ[EulerPhi[#] - 1]&] (* Vincenzo Librandi, Aug 13 2013 *)
PROG
(PARI) is(n)=isprime(eulerphi(n)-1) \\ Charles R Greathouse IV, Feb 21 2013
(Magma) [n: n in [1..200] | IsPrime(EulerPhi(n)-1)]; // Vincenzo Librandi, Aug 13 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Dec 12 2002
STATUS
approved