OFFSET
1,1
COMMENTS
Numbers n such that '43339' appended to n times the digit 8 is prime.
a(n) mod 7 <= 5 (zero or prime <= 5).
EXAMPLE
5 appears because 8888843339 ('8' concatenated 5 times and prepended to '43339') is prime.
MATHEMATICA
Select[ Range[2000], PrimeQ[(2^(#+8)*5^(#+5) - 409949) / 9] &] (* Or *)
Select[ Range[2000], PrimeQ[2*(2^(#+7)*5^(#+5) - 204979) / 9 + 1] &]
PROG
(PARI) is(n) = ispseudoprime((2^(n+8)*5^(n+5) - 409949) / 9); \\ Altug Alkan, Jan 15 2016
(Magma) [n: n in [0..500] |IsPrime((2^(n+8)*5^(n+5)-409949) div 9)]; // Vincenzo Librandi, Jan 16 2016
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Mikk Heidemaa, Jan 07 2016
STATUS
approved