OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..2000
EXAMPLE
1 is in the sequence because 331 is prime.
59 is in the sequence because 3359 is prime.
107 is in the sequence because 33107 is prime.
MAPLE
a:=proc(n) if isprime(33*10^nops(convert(n, base, 10))+n)=true then n else fi end: seq(a(n), n=0..600); # Emeric Deutsch, Sep 02 2005
MATHEMATICA
Select[Range[600], PrimeQ[33*10^IntegerLength[#]+#]&] (* Harvey P. Dale, Jul 29 2014 *)
PROG
(Magma) [ n: n in [1..600] | IsPrime(Seqint(Intseq(n) cat [3, 3])) ];
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Aug 24 2005
EXTENSIONS
More terms from Emeric Deutsch, Sep 02 2005
STATUS
approved