

A058590


Numbers k such that 5*3^k + 2 is prime.


1



0, 1, 2, 3, 5, 7, 10, 11, 13, 16, 28, 32, 56, 57, 62, 95, 111, 160, 308, 323, 855, 880, 1081, 1095, 1288, 2635, 2822, 2948, 3195, 7702, 8823, 10751, 11572, 12718, 14587, 20445, 26863, 28501, 29086, 30926, 37671, 38450, 57541, 81350, 214250
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OFFSET

1,3


COMMENTS

214250 also belongs to the sequence (but interval 35000209600 was not searched).  Serge Batalov, Oct 30 2010
a(45) > 2*10^5.  Robert Price, May 16 2015
Confirmed a(45) = 214250.  Robert Price, May 21 2015
a(46) > 215000.  Robert Price, May 21 2015


LINKS

Table of n, a(n) for n=1..45.


MATHEMATICA

Do[ If[ PrimeQ[ 5*3^n + 2 ], Print[ n ] ], {n, 0, 7550} ]
Select[Range[0, 2 10^3], PrimeQ[5 3^# + 2] &] (* Vincenzo Librandi, May 16 2015 *)


PROG

(MAGMA) [n: n in [0..1000]  IsPrime(5*3^n+2)]; // Vincenzo Librandi, May 16 2015
(PARI) is(n)=ispseudoprime(5*3^n+2) \\ Charles R Greathouse IV, Jun 13 2017
(PFGW) ABC2 5*3^$a + 2
a: from 0 to 10000 // Jinyuan Wang, Feb 01 2020


CROSSREFS

Cf. A058591 (5*3^k  2 is prime).
Sequence in context: A327203 A048461 A338174 * A187711 A064627 A324813
Adjacent sequences: A058587 A058588 A058589 * A058591 A058592 A058593


KEYWORD

nonn,more


AUTHOR

Robert G. Wilson v, Dec 26 2000


EXTENSIONS

More PRP terms from Serge Batalov, Oct 30 2010
a(41)a(44) from Robert Price, May 16 2015
a(1)=0 prepended by Vincenzo Librandi, May 16 2015
a(45) discovered by Serge Batalov added by Robert Price, May 21 2015


STATUS

approved



