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A093163
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Primes of the form 40*R_k + 3, where R_k is the repunit (A002275) of length k.
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2
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OFFSET
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1,1
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COMMENTS
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Primes of the form (4*10^k - 13)/9; the next term a(9) is a 183-digit number. - Vincenzo Librandi, Nov 16 2010
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LINKS
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MATHEMATICA
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f[n_] := (4*10^n-13)/9; Select[f[Range[50]], PrimeQ] (* Amiram Eldar, Nov 23 2018 *)
Select[Table[FromDigits[PadLeft[{3}, n, 4]], {n, 40}], PrimeQ] (* Harvey P. Dale, Dec 19 2022 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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