OFFSET
1,1
COMMENTS
11 and 19 are primes.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
7 is in the sequence because 11197 is prime.
73 is in the sequence because 111973 is prime.
221 is in the sequence because 1119221 is prime.
MAPLE
a:=proc(n) local z: z:=nops(convert(n, base, 10)): if isprime(1119*10^z+n)=true then n else fi end: seq(a(n), n=1..1000); # Emeric Deutsch, Jul 06 2005
MATHEMATICA
Select[Range[900], PrimeQ[FromDigits[Join[{1, 1, 1, 9}, IntegerDigits[#]]]]&] (* Harvey P. Dale, May 22 2012 *)
PROG
(Magma) [ n: n in [1..900] | IsPrime(Seqint(Intseq(n) cat [9, 1, 1, 1])) ];
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Jun 25 2005
EXTENSIONS
More terms from Emeric Deutsch, Jul 06 2005
STATUS
approved