OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..8
Makoto Kamada, Prime numbers of the form 533...33.
MATHEMATICA
Select[Table[FromDigits[PadRight[{5}, n, 3]], {n, 200}], PrimeQ] (* Harvey P. Dale, Jan 14 2012 *)
PROG
(Magma) [a: n in [0..200] | IsPrime(a) where a is (16*10^n-1) div 3 ]; // Vincenzo Librandi, Apr 07 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Rick L. Shepherd, Apr 08 2004
STATUS
approved