A229612 Numbers n such that (19^n + 5^n)/24 is prime.

11, 37, 107, 181, 449, 457, 3583, 9133, 10139, 99689

Offset

1,1

Comments

All terms are primes.

a(11) > 10^5.

Links

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

Mathematica

k=19; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n, 1, 9592}]

Prog

(PARI) is(n)=ispseudoprime((19^n+5^n)/24) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A128075, A228130, A225818.

Sequence in context: A316191 A003020 A075024 * A297797 A210321 A356278

Adjacent sequences: A229609 A229610 A229611 * A229613 A229614 A229615

Keyword

hard,more,nonn

Author

Robert Price, Sep 26 2013

Status

approved