OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..2500
EXAMPLE
k=103 is in the sequence because 3333k = 3333103 is prime.
MATHEMATICA
Select[Range[700], PrimeQ[FromDigits[Join[{3, 3, 3, 3}, IntegerDigits[#]]]] &] (* Vincenzo Librandi, Feb 03 2017 *)
PROG
(Magma) [n: n in [1..700] | IsPrime(Seqint(Intseq(n) cat [3, 3, 3, 3]))]; // Vincenzo Librandi, Feb 03 2017
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Sep 14 2005
STATUS
approved