OFFSET
1,2
COMMENTS
a(20) > 2*10^5. - Robert Price, May 12 2015
MATHEMATICA
Do[ If[ PrimeQ[ 7*3^n + 2 ], Print[ n ] ], {n, 1, 2500} ]
Select[Range[0, 10000], PrimeQ[(7*3^# + 2)] &] (* Vincenzo Librandi, Sep 29 2012 *)
PROG
(PARI) is(n)=ispseudoprime(7*3^n+2) \\ Charles R Greathouse IV, Jun 12 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Dec 26 2000
EXTENSIONS
a(13)-a(14) from Vincenzo Librandi, Sep 29 2012
a(15)-a(19) from Robert Price, May 12 2015
STATUS
approved