OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..2000
EXAMPLE
If n=1 then 66n = 661 which is a prime.
If n=91 then 66n = 6691 which is a prime.
MAPLE
a:= proc(n) local k; for k from 1 +`if`(n=1, 0, a(n-1))
while not isprime(parse(""||66||k)) do od; a(n):=k
end:
seq(a(n), n=1..100); # Alois P. Heinz, Jul 30 2014
MATHEMATICA
Select[Range[700], PrimeQ[66 10^IntegerLength[#] + #] &] (* Vincenzo Librandi, Jul 30 2014 *)
PROG
(Magma) [n: n in [1..600] | IsPrime(Seqint(Intseq(n) cat [6, 6])) ]; // Vincenzo Librandi, Jul 30 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Parthasarathy Nambi, Aug 30 2005
EXTENSIONS
More terms from Vincenzo Librandi, Mar 27 2010
STATUS
approved