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A110980 Integers n such that 10^n+99 is prime. 4
1, 2, 4, 6, 13, 14, 16, 17, 19, 30, 31, 60, 68, 73, 113, 144, 276, 288, 364, 449, 473, 739, 833, 1171, 1732, 2292, 3912, 7673, 9458, 16982, 19751, 21479, 23837, 77726 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The next term, if one exists, is >100000. - Robert Price, Apr 25 2011

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "10w99".

LINKS

Table of n, a(n) for n=1..34.

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

Index entries for primes involving repunits.

EXAMPLE

If n=6, we have 10^6+99 = 1000000+99 = 1000099, which is prime.

MATHEMATICA

Select[Range[78000], PrimeQ[10^#+99]&] (* Harvey P. Dale, Aug 23 2013 *)

PROG

(MAGMA) [n: n in [1..400]| IsPrime(10^n+99)]; // Vincenzo Librandi, Nov 02 2014

CROSSREFS

Cf. A049054, A088274, A088275, A095688, A107083, A108049, A108050, A108052, A108054.

Sequence in context: A261206 A127105 A196444 * A058598 A278031 A087549

Adjacent sequences:  A110977 A110978 A110979 * A110981 A110982 A110983

KEYWORD

more,nonn

AUTHOR

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

EXTENSIONS

a(1)=1 added by Vladimir Joseph Stephan Orlovsky, May 02 2008

a(29)-a(33) from Robert Price, Mar 22 2010

a(34)=77726 from Robert Price, Mar 03 2011

STATUS

approved

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Last modified September 26 05:09 EDT 2017. Contains 292502 sequences.