A058591 - OEIS

%I #21 Sep 08 2022 08:45:02

%S 0,1,2,5,6,8,11,12,14,17,26,47,59,65,83,92,96,110,113,186,527,834,

%T 1274,5124,5750,7616,11328,54287,57186

%N Numbers k such that 5*3^k - 2 is prime.

%C No further terms <= 55000. - _Serge Batalov_, Oct 31 2010

%C a(30) > 2*10^5. - _Robert Price_, May 20 2015

%t Do[ If[ PrimeQ[ 5*3^n - 2 ], Print[ n ] ], {n, 0, 4200} ]

%o (Magma) [n: n in [0..1000] | IsPrime(5*3^n-2)]; // _Vincenzo Librandi_, May 21 2015

%o (PARI) is(n)=ispseudoprime(5*3^n-2) \\ _Charles R Greathouse IV_, Jun 13 2017

%o (PFGW) ABC2 5*3^$a - 2

%o a: from 0 to 10000 // _Jinyuan Wang_, Feb 01 2020

%Y Cf. A058590 (5*3^k + 2 is prime).

%K nonn,more

%O 1,3

%A _Robert G. Wilson v_, Dec 26 2000

%E Corrected by and more PRP terms from _Serge Batalov_, Oct 31 2010

%E a(29) from _Robert Price_, May 20 2015

%E Added 0 from _Vincenzo Librandi_, May 21 2015