OFFSET
1,2
COMMENTS
Also, numbers k such that (10^k + 29)/3 is prime.
Terms from Kamada data. Note Kamada does not recognize k=1 as 13 is a degenerate case of form AAA..ABA.
a(21) > 2.5*10^5.
LINKS
EXAMPLE
For k=4, 3*R_4 + 10 = 3333 + 10 = 3343 which is prime.
MATHEMATICA
Select[Range[0, 250000], PrimeQ[(10^# + 29)/3] &]
PROG
(Magma) [n: n in [0..400] | IsPrime((10^n+29) div 3)]; // Vincenzo Librandi, Apr 11 2015
CROSSREFS
KEYWORD
more,hard,nonn
AUTHOR
Robert Price, Apr 10 2015
STATUS
approved