A108332 - OEIS

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A108332

Integers k such that 10^k - 89 is prime.

2

2, 3, 637, 2349, 29455, 175093

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

637 corresponds to a certified prime (Primo 2.2.0 beta). - Ryan Propper, Nov 06 2005

No additional terms < 40000.

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "9w11".

LINKS

Table of n, a(n) for n=1..6.

Makoto Kamada, List of near-repdigit-related prime numbers.

Index entries for primes involving repunits.

EXAMPLE

k = 3 is a term because 10^3 - 89 = 1000 - 89 = 911, which is prime.

MATHEMATICA

Do[If[PrimeQ[10^n - 89], Print[n]], {n, 2, 10^4}] (* Ryan Propper, Nov 06 2005 *)

CROSSREFS

Cf. A089675, A095714, A092767.

Sequence in context: A264577 A165770 A226148 * A256115 A066685 A076155

Adjacent sequences: A108329 A108330 A108331 * A108333 A108334 A108335

KEYWORD

nonn,more

AUTHOR

Julien Peter Benney (jpbenney(AT)ftml.net), Jun 30 2005

EXTENSIONS

a(5) from Robert Price, Dec 15 2010

Edited by Ray Chandler, Dec 23 2010

a(6) from Riley Fisher, Oct 09 2023

STATUS

approved