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A108365 Integers n such that 10^n - 39 is prime. 0
2, 5, 6, 12, 17, 19, 61, 102, 195, 447, 1250, 1329, 1935, 3930, 5837, 7176, 8724, 20881, 23936, 61868, 91920 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99961".

LINKS

Table of n, a(n) for n=1..21.

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

Index entries for primes involving repunits.

EXAMPLE

If n=2 then 10^n - 39 = 61 (prime).

If n=61 then 10^n - 39 = 9999999999999999999999999999999999999999999999999999999999961 (prime).

CROSSREFS

Cf. A108330, A108328.

Sequence in context: A085206 A238481 A058601 * A064765 A257805 A082552

Adjacent sequences:  A108362 A108363 A108364 * A108366 A108367 A108368

KEYWORD

more,nonn

AUTHOR

Parthasarathy Nambi, Jul 01 2005

EXTENSIONS

a(8)-a(12) from Stefan Steinerberger, Nov 05 2005

a(13)-a(19) from Robert Price, Dec 12 2010

Edited by Ray Chandler, Dec 23 2010

a(20)=61868, a(21)=91920 from Robert Price, Apr 25 2011

STATUS

approved

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