OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..11
MATHEMATICA
t={}; Do[m=n; p=10^n+10^(n-2)-1; If[PrimeQ[p], AppendTo[t, p]], {n, 300}]; t (* Vincenzo Librandi, Jul 17 2012 *)
Select[Table[10^n+10^(n-2)-1, {n, 50}], PrimeQ] (* Harvey P. Dale, Apr 13 2019 *)
PROG
(PARI) f(n, z) = for(x=z, n, y=10^x+10^(x-z)-1; if(ispseudoprime(y), print1(y", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Cino Hilliard, Jul 28 2004
STATUS
approved