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 A108654 Numbers n such that 10^n - 117 is prime. 0

%I

%S 3,4,6,7,9,15,27,40,72,134,170,204,237,240,285,288,592,613,1443,1524,

%T 2289,2292

%N Numbers n such that 10^n - 117 is prime.

%e If n=3 then 10^n - 117 = 883 (prime).

%e If n=40 then 10^n - 117 = 9999999999999999999999999999999999999883 (prime).

%p a := proc (n) if isprime(10^n-117) = true then n else end if end proc; seq(a(n), n = 1 .. 1500); - _Emeric Deutsch_, Jul 09 2007

%t Select[Range[3,2500],PrimeQ[10^#-117]&] (* _Harvey P. Dale_, Feb 18 2011 *)

%o (PARI) is(n)=ispseudoprime(10^n-117) \\ _Charles R Greathouse IV_, Jun 13 2017

%K hard,nonn

%O 1,1

%A _Parthasarathy Nambi_, Jul 06 2005

%E More terms from _Emeric Deutsch_, Jul 09 2007

%E More terms from Harvey P. Dale, Feb 18 2011

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Last modified November 12 13:36 EST 2018. Contains 317109 sequences. (Running on oeis4.)