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A104065
Primes of the form 7^k + 4.
8
5, 11, 53, 347, 16811, 823547, 40353611, 678223072853, 27368747340080916347
OFFSET
1,1
MATHEMATICA
a = Delete[Union[Flatten[Table[If [PrimeQ[7^n + 3 + 1] == True, 7^n + 3 + 1, 0], {n, 1, 400}]]], 1]
Select[7^Range[0, 30]+4, PrimeQ] (* Harvey P. Dale, Jul 31 2021 *)
CROSSREFS
Sequence in context: A149527 A201180 A109546 * A212304 A018545 A028349
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Mar 02 2005
EXTENSIONS
Initial 5 from Vincenzo Librandi, Dec 10 2010
STATUS
approved