

A243397


Numbers n such that 19^n+4 is prime.


2




OFFSET

1,3


COMMENTS

No further terms up to 20000.  Felix Fröhlich, Oct 29 2014
No further terms up to 24000.  Felix Fröhlich, Jan 22 2015


LINKS

Table of n, a(n) for n=1..10.


MATHEMATICA

Select[Range[0, 10000], PrimeQ[19^# + 4] &] (* Vincenzo Librandi, Oct 16 2014 *)


PROG

(PARI) for(n=0, 10^5, if(ispseudoprime(19^n+4), print1(n, ", ")))
(MAGMA) [n: n in [0..1000]  IsPrime(19^n+4)]; // Vincenzo Librandi, Oct 16 2014


CROSSREFS

Corresponding sequences for k^n+4: A058958 (k=3), A124621 (k=5), A096305 (k=7), A217384 (k=9), A137236 (k=13).
Sequence in context: A228115 A033888 A141492 * A173350 A323203 A169634
Adjacent sequences: A243394 A243395 A243396 * A243398 A243399 A243400


KEYWORD

nonn,more


AUTHOR

Felix Fröhlich, Jun 04 2014


EXTENSIONS

a(1)a(2) prepended by N. J. A. Sloane, Jun 18 2014
a(9)a(10) from Felix Fröhlich, Oct 16 2014


STATUS

approved



