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Integers k such that 10^k + 87 is a prime number.
1

%I #22 Jan 25 2022 08:46:17

%S 1,3,9,19,39,43,121,153,1243,14445,15273,26779

%N Integers k such that 10^k + 87 is a prime number.

%C The next term, if one exists, is > 100000. - _Robert Price_, Apr 25 2011

%C See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "10087".

%H Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/">List of near-repdigit-related prime numbers</a>.

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

%e 3 is a term because 10^3 + 87 = 1000 + 87 = 1087, which is a prime number.

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

%K nonn,more

%O 1,2

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

%E Term 14445 from _Robert Price_, Mar 22 2010

%E Terms 1243, 15273, 26779 from _Robert Price_, Oct 04 2010

%E Edited by _Ray Chandler_, Dec 23 2010