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A125957 Numbers n such that (2^n + 11^n)/13 is prime. 4
3, 5, 17, 67, 83, 101, 1373, 6101, 12119, 61781 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

a(11) > 10^5. - Robert Price, Feb 26 2013

LINKS

Table of n, a(n) for n=1..10.

MATHEMATICA

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

PROG

(PARI) is(n)=ispseudoprime((2^n+11^n)/13) \\ Charles R Greathouse IV, Feb 20 2017

CROSSREFS

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.

Sequence in context: A265425 A256438 A251737 * A259908 A137460 A319908

Adjacent sequences:  A125954 A125955 A125956 * A125958 A125959 A125960

KEYWORD

hard,more,nonn

AUTHOR

Alexander Adamchuk, Feb 06 2007

EXTENSIONS

2 more terms from Ryan Propper, Feb 09 2008

a(9)-a(10) from Robert Price, Feb 26 2013

STATUS

approved

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Last modified November 15 09:03 EST 2019. Contains 329144 sequences. (Running on oeis4.)