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Primes of the form 10^n - 59.
1

%I #14 Feb 08 2024 11:41:14

%S 41,941,9941,99999941,99999999999999999941,

%T 99999999999999999999999999999999999941,

%U 99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999941

%N Primes of the form 10^n - 59.

%C The next term (a(8)) has 248 digits. [From Harvey P. Dale, Dec 29 2011]

%t Select[10^Range[0,400] - 59,PrimeQ] (* _Harvey P. Dale_, Dec 29 2011 *)

%t Select[Table[FromDigits[PadLeft[{4,1},n,9]],{n,2,400}],PrimeQ] (* _Harvey P. Dale_, Feb 08 2024 *)

%o (Magma) [a: n in [2..250] | IsPrime(a) where a is 10^n-59];

%Y Cf. A108506.

%K nonn

%O 1,1

%A _Vincenzo Librandi_, Dec 11 2010