OFFSET
1,1
COMMENTS
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..16
Makoto Kamada, Prime numbers of the form 799...993.
FORMULA
a(n) = 8*A099190(n) - 7.
EXAMPLE
7993 is in the sequence because 7993=8*10^3-7 and 7993 is prime.
MATHEMATICA
Do[If[PrimeQ[8*10^n - 7], Print[8*10^n - 7]], {n, 60}]
Select[Table[8*10^n-7, {n, 0, 80}], PrimeQ] (* Vincenzo Librandi, Jul 19 2012 *)
PROG
(Magma) [ a: n in [0..50] | IsPrime(a) where a is 8*10^n-7 ]; // Vincenzo Librandi, Jul 19 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Farideh Firoozbakht, Apr 16 2005
STATUS
approved