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Integers n such that 10^n+39 is a prime number.
1

%I #23 Sep 08 2022 08:45:32

%S 2,3,4,6,8,12,20,72,196,676,1528,1923,5244,5379,6308,21222,81778

%N Integers n such that 10^n+39 is a prime number.

%H Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/">List of near-repdigit-related prime numbers</a>. (See primecount.txt for terms, primesize.txt for discovery details, including probable or proved primes - search on "10039")

%H <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.

%e 6 is a member: 10^6+39 = 1000000+39 = 1000039, which is a prime number.

%t Select[Range[2000], PrimeQ[10^# + 39] &] (* _G. C. Greubel_, Sep 23 2016 *)

%o (Magma) [n: n in [0..500] |IsPrime(10^n+39)]; // _Vincenzo Librandi_, Sep 24 2016

%Y Cf. A095688, A108052, A108050, A108312, A107083, A108049, A108054.

%K more,nonn

%O 1,1

%A Julien Peter Benney (jpbenney(AT)gmail.com), Feb 12 2008

%E a(11)-a(12) from _Harvey P. Dale_, May 25 2008

%E a(13)-a(16) from _Robert Price_, Jan 30 2010

%E Edited by _Ray Chandler_, Dec 23 2010

%E a(17) from _Robert Price_, Mar 03 2011