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

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

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 * A374150 A259908 A137460

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