A093165 - OEIS

A093165

Primes of the form 70*R_k + 3, where R_k is the repunit (A002275) of length k.

3, 73, 773, 77773, 777777773, 777777777773, 777777777777773, 777777777777777777773

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OFFSET

1,1

COMMENTS

Primes of the form (7*10^k - 43)/9. - Vincenzo Librandi, Nov 16 2010

The next term, a(9), has 264 digits. - Harvey P. Dale, Jul 19 2012

LINKS

MATHEMATICA

Select[Table[FromDigits[PadLeft[{3}, n, 7]], {n, 500}], PrimeQ] (* Harvey P. Dale, Jul 19 2012 *)

CROSSREFS

Cf. A056689 (corresponding k), A099420.

KEYWORD

nonn

AUTHOR

STATUS

approved