

A057469


Prime numbers k such that (2^k + 3^k)/5 is prime.


26



3, 7, 11, 83, 149, 223, 599, 647, 1373, 8423, 149497, 388897
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..12.


MATHEMATICA

Do[ If[ PrimeQ[ n ], If[ PrimeQ[ (3^n + 2^n)/5 ], Print[ n ] ] ], {n, 0, 6270} ]


PROG

(PARI) is(n)=isprime(n) && ispseudoprime((2^n + 3^n)/5) \\ Charles R Greathouse IV, Apr 28 2015
(Magma) [p: p in [3..1000]  IsPrime(p) and IsPrime((2^p + 3^p) div 5)]; // Jinyuan Wang, Dec 22 2019


CROSSREFS

Cf. A127908 (primes of the form (3^k+2^k)/5).
Sequence in context: A016081 A287301 A105762 * A247229 A082598 A082599
Adjacent sequences: A057466 A057467 A057468 * A057470 A057471 A057472


KEYWORD

nonn,more


AUTHOR

Robert G. Wilson v, Sep 09 2000


EXTENSIONS

More terms from Kamil Duszenko (kdusz(AT)wp.pl), Apr 11 2003
Definition corrected by Alexander Adamchuk, Feb 06 2007
a(11) corresponding to a probable prime with 71328 digits from JeanLouis Charton, Oct 14 2010
a(12) corresponding to a probable prime with 185551 digits from JeanLouis Charton, Sep 18 2011


STATUS

approved



