OFFSET
1,1
COMMENTS
All terms are prime.
a(13) > 10^5.
MATHEMATICA
Select[ Prime[ Range[1, 100000] ], PrimeQ[ (11^# - 2^#)/9 ]& ]
PROG
(PARI) is(n)=isprime((11^n-2^n)/9) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Robert Price, Jan 25 2013
STATUS
approved