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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, 531611, 2052329 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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
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 Jean-Louis Charton, Oct 14 2010
a(12) corresponding to a probable prime with 185551 digits from Jean-Louis Charton, Sep 18 2011
a(13) corresponding to a probable prime with 253643 digits from Ryan Propper, Dec 10 2023
a(14) corresponding to a probable prime with 979210 digits from Ryan Propper, Dec 10 2023
STATUS
approved

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Last modified May 23 00:00 EDT 2024. Contains 372758 sequences. (Running on oeis4.)