OFFSET
1,2
COMMENTS
a(20) > 2*10^5. - Robert Price, Jun 23 2015
MATHEMATICA
Do[ f = 15^n - 2; If[ PrimeQ[ f ], Print[ {n, f} ] ], {n, 1, 1000} ]
Do[If[PrimeQ[15^n - 2], Print[n]], {n, 10^4}] (* Ryan Propper, Jun 06 2007 *)
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Alexander Adamchuk, Mar 14 2007
EXTENSIONS
550 from Stefan Steinerberger, May 05 2007
3 more terms from Ryan Propper, Jun 06 2007
a(14)-a(19) from Robert Price, Jun 23 2015
STATUS
approved