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A105322
Primes of the form 8*10^n-7.
3
73, 7993, 799993, 7999993, 79999999993, 7999999999993, 79999999999993, 7999999999999999999999999999999999999993, 7999999999999999999999999999999999999999999999993
OFFSET
1,1
COMMENTS
This sequence is a subsequence of A104907 also is a subsequence of A105324(see A104907 and A105324).
LINKS
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