OFFSET
1,1
COMMENTS
a(n) = 0 is confirmed only for k <= 5000, they are not definite.
EXAMPLE
(1^1+3)/(1+3) = 1 is not prime. (2^2+3)/(2+3) = 7/5 is not prime. (3^3+3)/(3+3) = 30/6 = 5 is prime. Thus a(3)= 3.
PROG
(PARI) a(n)=for(k=1, 1500, s=(k^k+n)/(k+n); if(floor(s)==s, if(ispseudoprime(s), return(k))));
n=1; while(n<100, print(a(n)); n+=1)
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
Derek Orr, May 23 2014
STATUS
approved