OFFSET
1,1
COMMENTS
Note that p^2 - p + 1 = p * phi(p) + 1 when p is prime.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Table[p = Prime[n]; p*EulerPhi[p] + 1, {n, 270}], PrimeQ] (* Arkadiusz Wesolowski, Dec 13 2011 *)
Select[Table[p^2-p+1, {p, Prime[Range[300]]}], PrimeQ] (* Harvey P. Dale, Sep 22 2015 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Enoch Haga, Jan 16 2004
STATUS
approved