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A093163 Primes of the form 40*R_n + 3, where R_n is the repunit (A002275) of length n. 2
3, 43, 443, 444443, 444444443, 444444444443, 444444444444444444444444444443, 44444444444444444444444444444443 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes of the form (4*10^n-13)/9; the next term a(9) is a 183-digit number. - Vincenzo Librandi, Nov 16 2010

LINKS

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

Makoto Kamada, Prime numbers of the form 44...443.

Index entries for primes involving repunits

MATHEMATICA

f[n_] := (4*10^n-13)/9; Select[f[Range[50]], PrimeQ] (* Amiram Eldar, Nov 23 2018 *)

CROSSREFS

Cf. A056661 (corresponding n), A173770.

Sequence in context: A036940 A099664 A173770 * A199020 A211959 A283514

Adjacent sequences:  A093160 A093161 A093162 * A093164 A093165 A093166

KEYWORD

nonn

AUTHOR

Rick L. Shepherd, Mar 26 2004

STATUS

approved

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Last modified August 3 05:55 EDT 2020. Contains 336197 sequences. (Running on oeis4.)