OFFSET
1,1
COMMENTS
Also, numbers k such that (71*10^k - 17)/9 is prime.
Terms from Kamada data.
LINKS
EXAMPLE
For k=2, 8*R_2 + 7*10^k - 1 = 88 + 700 - 1 = 787 which is prime.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[(71*10^#-17)/9] &]
PROG
(Magma) [n: n in [0..300] | IsPrime((71*10^n-17)div 9)]; // Vincenzo Librandi, Jun 19 2015
CROSSREFS
KEYWORD
more,hard,nonn
AUTHOR
Robert Price, Jun 18 2015
STATUS
approved