login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 (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

(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 Jean-Louis Charton, Oct 14 2010

a(12) corresponding to a probable prime with 185551 digits from Jean-Louis Charton, Sep 18 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 9 23:05 EST 2022. Contains 358710 sequences. (Running on oeis4.)