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A057469 Prime numbers n such that (2^n + 3^n)/5 is prime. 24
3, 7, 11, 83, 149, 223, 599, 647, 1373, 8423, 149497, 388897 (list; graph; refs; listen; history; text; internal format)
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

CROSSREFS

Primes of form (3^n + 2^n)/5 are listed in A127908.

Sequence in context: A016081 A287301 A105762 * A247229 A082598 A082599

Adjacent sequences:  A057466 A057467 A057468 * A057470 A057471 A057472

KEYWORD

nonn

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

New term 149497 found by Jean-Louis Charton on Oct 14 2010 corresponding to a probable prime with 71328 digits. Jean-Louis Charton, Oct 18 2010

New term 388897 found by Jean-Louis Charton in Sep 18 2011 corresponding to a probable prime with 185551 digits.

STATUS

approved

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Last modified July 22 03:22 EDT 2017. Contains 289648 sequences.