OFFSET
1,2
COMMENTS
Also numbers k such that (22*10^k - 13)/9 is prime.
a(21) > 2*10^5. - Robert Price, Jun 11 2018
LINKS
FORMULA
a(n) = A101958(n) + 1.
MATHEMATICA
Do[ If[ PrimeQ[(22*10^n - 13)/9], Print[n]], {n, 0, 10000}]
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Robert G. Wilson v, Dec 17 2004
EXTENSIONS
a(14)-a(16) from Erik Branger May 01 2013 by Ray Chandler, Aug 16 2013
a(17)-a(18) from Robert Price, Mar 16 2015
a(19)-a(20) from Robert Price, Jun 11 2018
STATUS
approved