OFFSET
1,1
EXAMPLE
n = 2, 4, and 6, yield (23*10^n - 26)/6 = 379, 38329, and 3833329, respectively, which are prime.
MATHEMATICA
fQ[n_] := PrimeQ[(23*10^n - 26)/6]; Select[ Range@ 10000, fQ] (* Robert G. Wilson v, Jan 28 2015 *)
PROG
(PARI) is(n)=ispseudoprime((23*10^n-26)/6) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Hans Havermann, Jan 24 2015
STATUS
approved