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A169716 Numbers n such that 2^n-127 is prime. 2

%I

%S 47,55,103,143,391,2807,11647,19223

%N Numbers n such that 2^n-127 is prime.

%C Exponents n arising in A175347: see that sequence for the actual primes.

%C The next term is > 10^4. [M. F. Hasler, Apr 18 2010]

%C All terms are == 7 (mod 8). [Hasler]

%C No more terms through 78815. - _Charles R Greathouse IV_, Apr 19 2010

%H Charles R Greathouse IV, <a href="http://list.seqfan.eu/pipermail/seqfan/2010-April/004363.html">Re: A175347: Primes in A176303</a>, seqfan list, Apr 19 2010.

%o (PARI) is(n)=ispseudoprime(2^n-127) \\ _Charles R Greathouse IV_, Sep 14 2015

%Y Cf. A175347, A176303.

%K nonn

%O 1,1

%A _Zak Seidov_, Apr 18 2010

%E More terms from _M. F. Hasler_, Apr 18 2010

%E a(7), a(8) from _Charles R Greathouse IV_, Apr 19 2010

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Last modified February 26 01:41 EST 2020. Contains 332270 sequences. (Running on oeis4.)