OFFSET
1,2
COMMENTS
a(9) > 5000, if it exists. - Amiram Eldar, Jun 28 2024
MATHEMATICA
Select[Range[1000], PrimeQ[(# + 1)^# + #^(# - 1)] &] (* Vincenzo Librandi, Sep 27 2012 *)
PROG
(PARI) xp1toxp1(n)= { my(y); forstep(x=1, n, 1, y=(x+1)^x + x^(x-1); if(ispseudoprime(y), print1(x, ", ")) ); }
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Cino Hilliard, Aug 30 2003
EXTENSIONS
a(1)=1 inserted by Vincenzo Librandi, Sep 27 2012
STATUS
approved