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A093165 Primes of the form 70*R_n + 3, where R_n is the repunit (A002275) of length n. 4
3, 73, 773, 77773, 777777773, 777777777773, 777777777777773, 777777777777777777773 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

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

LINKS

Table of n, a(n) for n=1..8.

Makoto Kamada, Prime numbers of the form 77...773.

Index entries for primes involving repunits

MATHEMATICA

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

CROSSREFS

Cf. A056689 (corresponding n), A099420.

Sequence in context: A060883 A162601 A173807 * A189306 A012810 A020517

Adjacent sequences:  A093162 A093163 A093164 * A093166 A093167 A093168

KEYWORD

nonn

AUTHOR

Rick L. Shepherd, Mar 26 2004

STATUS

approved

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Last modified December 14 17:55 EST 2019. Contains 329979 sequences. (Running on oeis4.)