OFFSET
1,1
COMMENTS
Primes of the form (19*10^n-1)/9.
The next term (a(9)) has 544 digits. Harvey P. Dale, Sep 28 2015
LINKS
FORMULA
a(n) = (19*10^A056700(n)-1)/9.
MATHEMATICA
Select[Table[FromDigits[Join[{2}, PadRight[{}, n, 1]]], {n, 0, 130}], PrimeQ] (* Harvey P. Dale, Sep 28 2015 *)
PROG
(PARI) for(n=0, 200, if(isprime(2*10^n+(10^(n)-1)/9)==1, print1(2*10^n+(10^(n)-1)/9, ", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Mar 07 2002
EXTENSIONS
More terms from Benoit Cloitre, Mar 09 2002
Edited by Ray Chandler, Feb 03 2012
STATUS
approved