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 A125957 Numbers n such that (2^n + 11^n)/13 is prime. 4

%I

%S 3,5,17,67,83,101,1373,6101,12119,61781

%N Numbers n such that (2^n + 11^n)/13 is prime.

%C All terms are primes. Corresponding primes of the form (2^n + 11^n)/13 are {103, 12391, 38880540653801911, ...}.

%C a(11) > 10^5. - _Robert Price_, Feb 26 2013

%t Do[p=Prime[n];f=(2^p+11^p)/13; If[PrimeQ[f], Print[{p, f}]], {n, 1, 100}]

%o (PARI) is(n)=ispseudoprime((2^n+11^n)/13) \\ _Charles R Greathouse IV_, Feb 20 2017

%Y Cf. A000978 = numbers n such that (2^n + 1)/3 is prime. Cf. A057469 = numbers n such that (2^n + 3^n)/5 is prime. Cf. A082387 = numbers n such that (2^n + 5^n)/7 is prime.

%K hard,more,nonn

%O 1,1

%A _Alexander Adamchuk_, Feb 06 2007

%E 2 more terms from _Ryan Propper_, Feb 09 2008

%E a(9)-a(10) from _Robert Price_, Feb 26 2013

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Last modified June 17 22:17 EDT 2019. Contains 324200 sequences. (Running on oeis4.)