OFFSET
1,2
COMMENTS
a(8) > 50000. - Jens Kruse Andersen, Aug 10 2014
PROG
(Magma) [n: n in [1..700] | IsPrime(10^n-2^n-1) ]
(PARI) is(n)=ispseudoprime(10^n-2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Vincenzo Librandi, Mar 11 2010
EXTENSIONS
a(6)-a(7) from Jens Kruse Andersen, Aug 10 2014
STATUS
approved