# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a057469 Showing 1-1 of 1 %I A057469 #29 Jan 16 2024 16:33:07 %S A057469 3,7,11,83,149,223,599,647,1373,8423,149497,388897,531611,2052329 %N A057469 Prime numbers k such that (2^k + 3^k)/5 is prime. %t A057469 Do[ If[ PrimeQ[ n ], If[ PrimeQ[ (3^n + 2^n)/5 ], Print[ n ] ] ], {n, 0, 6270} ] %o A057469 (PARI) is(n)=isprime(n) && ispseudoprime((2^n + 3^n)/5) \\ _Charles R Greathouse IV_, Apr 28 2015 %o A057469 (Magma) [p: p in [3..1000] | IsPrime(p) and IsPrime((2^p + 3^p) div 5)]; // _Jinyuan Wang_, Dec 22 2019 %Y A057469 Cf. A127908 (primes of the form (3^k+2^k)/5). %K A057469 nonn,more %O A057469 1,1 %A A057469 _Robert G. Wilson v_, Sep 09 2000 %E A057469 More terms from Kamil Duszenko (kdusz(AT)wp.pl), Apr 11 2003 %E A057469 Definition corrected by _Alexander Adamchuk_, Feb 06 2007 %E A057469 a(11) corresponding to a probable prime with 71328 digits from _Jean-Louis Charton_, Oct 14 2010 %E A057469 a(12) corresponding to a probable prime with 185551 digits from _Jean-Louis Charton_, Sep 18 2011 %E A057469 a(13) corresponding to a probable prime with 253643 digits from _Ryan Propper_, Dec 10 2023 %E A057469 a(14) corresponding to a probable prime with 979210 digits from _Ryan Propper_, Dec 10 2023 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE