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 A243397 Numbers n such that 19^n+4 is prime. 2
 0, 1, 3, 21, 145, 273, 1425, 9613, 15711, 18445 (list; graph; refs; listen; history; text; internal format)
 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 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

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Last modified December 1 16:44 EST 2021. Contains 349430 sequences. (Running on oeis4.)