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A093011 Primes of the form 10*R_k + 3, where R_k is the repunit (A002275) of length k. 3
3, 13, 113, 11113, 111111113, 11111111113, 111111111111111111111113, 111111111111111111111111111111111111111111111111111111111111111111111111111111111113 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes of the form 2 + (10^k - 1)/9, k > 0. - Vincenzo Librandi, Dec 13 2011

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..9

Makoto Kamada, Prime numbers of the form 11...113.

Index entries for primes involving repunits

MATHEMATICA

Select[Table[(((10^n-1)/ 9)+2), {n, 1, 900}], PrimeQ] (* Vincenzo Librandi, Dec 13 2011 *)

PROG

(MAGMA) [a: n in [1..100] | IsPrime(a) where a is ((10^n-1) div 9)+2 ]; // Vincenzo Librandi, Dec 13 2011

CROSSREFS

Cf. A056654 (corresponding k).

Sequence in context: A053583 A077713 A119723 * A262147 A057865 A260847

Adjacent sequences:  A093008 A093009 A093010 * A093012 A093013 A093014

KEYWORD

nonn

AUTHOR

Rick L. Shepherd, Mar 14 2004

STATUS

approved

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Last modified April 26 08:16 EDT 2019. Contains 322472 sequences. (Running on oeis4.)