A177508 - OEIS

%I #10 Sep 08 2022 08:45:53

%S 13,193,1993,19993,1999993,19999999999999993,1999999999999999999993,

%T 19999999999999999999999999993,

%U 1999999999999999999999999999999999999999999999993,19999999999999999999999999999999999999999999999999999999999999999999999999999999993

%N Primes of the form 2*10^n-7.

%t Select[2*10^Range[100]-7, PrimeQ] (* _Harvey P. Dale_, Jan 27 2015 *)

%o (Magma)[a: n in [1..250]|IsPrime(a) where a is (2*10^n-7)]

%Y Cf. A102946.

%K nonn

%O 1,1

%A _Vincenzo Librandi_, Dec 11 2010

%E One more term (a(10)) from _Harvey P. Dale_, Jan 27 2015