OFFSET
0,1
COMMENTS
Next term is greater than 2*10^8.
EXAMPLE
For k=0,1,...,6 3^3^k + 390410 are prime and 390410 is the smallest number with this property so a(6)=390410.
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Farideh Firoozbakht, May 13 2007, Jun 01 2007
STATUS
approved