OFFSET
1,1
COMMENTS
Also, numbers k such that (34*10^k - 43)/9 is prime.
Terms from Kamada data.
a(20) > 10^5.
LINKS
EXAMPLE
For k=2, 7*R_2 + 3*10^k - 4 = 77 + 300 - 4 = 373 which is prime.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[(34*10^#-43)/9] &]
PROG
(Magma) [n: n in [0..450] | IsPrime((34*10^n-43) div 9)]; // Vincenzo Librandi, Jun 19 2015
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Robert Price, Jun 18 2015
STATUS
approved