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%I #30 Jan 17 2019 13:44:08
%S 1,2,3,14,18,44,54,89,469,2060,2985,6197,16452,19393,21205,49657,
%T 74670,76374
%N Integers n such that 10^n + 31 is prime.
%C The next term, if one exists, is >100000. - _Robert Price_, Apr 26 2011
%C See Kamada link - primecount.txt for terms, primesize.txt for discovery details including proofs of primality - search on "10031".
%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 For n = 3 we get 10^3 + 31 = 1000 + 31 = 1031, which is prime.
%t a={}; Do[If[PrimeQ[p=10^n+31], AppendTo[a, n]], {n, 0, 6*10^2}]; a (* _Vladimir Joseph Stephan Orlovsky_, Aug 07 2008 *)
%Y Cf. A049054, A088274, A088275, A095688, A108052, A108050, A108049, A108054.
%K more,nonn
%O 1,2
%A Julien Peter Benney (jpbenney(AT)ftml.net), Jun 08 2005
%E 16452 and 19393 from _Robert Price_, Mar 22 2010
%E Additional term (21205) from _Robert Price_, May 24 2010
%E Missing term (6197) added by _Robert Price_, Dec 07 2010
%E Edited by _Ray Chandler_, Dec 23 2010
%E a(16)=49657 from _Robert Price_, Dec 31 2010
%E a(17)=74670 from _Robert Price_, Jan 29 2011
%E a(18)=76374 from _Robert Price_, Mar 03 2011
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