OFFSET
1,1
COMMENTS
a(6) > 22000. - Giovanni Resta, Jun 12 2017
EXAMPLE
a(1) = 2 because 3*2^2-1 = 11 a prime.
a(2) = 6 because 13*6^6-1 = 606527 a prime.
MATHEMATICA
Select[Range[1000], PrimeQ[Prime[#] #^# - 1] &]
PROG
(Magma) [n: n in [1..1000] | IsPrime(NthPrime(n)*n^n-1)];
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Vincenzo Librandi, Jun 10 2017
STATUS
approved