%I
%S 2,3,19,30,535,1551,7069,8508
%N Numbers k such that k^k + k  1 is prime.
%C Except for the first term all terms are of the form 3k or 3k+1.  _Farideh Firoozbakht_, Oct 18 2006
%C Corresponding values of primes are in A187605.  _Jaroslav Krizek_, Nov 14 2013
%C If it exists, a(9) > 16100.  _Hugo Pfoertner_, Mar 02 2020
%e 3 is a term because 3^3 + 3  1 = 29.
%t Do[ If[ PrimeQ[ n^n + n  1], Print[n]], {n, 1, 750} ]
%o (PARI) is(n)=ispseudoprime(n^n+n1) \\ _Charles R Greathouse IV_, Feb 20 2017
%Y Cf. A058911 (k^k + k + 1 is prime).
%K nonn,more,hard
%O 1,1
%A _Felice Russo_, Jan 10 2001
%E a(6) from _Farideh Firoozbakht_, Oct 18 2006
%E a(7)a(8) from _Hugo Pfoertner_, Mar 02 2020
