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%I #40 Jul 10 2023 09:53:20
%S 1,2,3,5,8,17,24,32,65,66,67,79,83,98,152,260,781,1225,1777,2023,2411,
%T 3469,5347,10646,11335,13989,14792,16731,19015,29471,39187,41456,
%U 80883,102824,154359,216950,294475
%N Integers k such that 10^k+49 is prime.
%C See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "10049".
%C a(38) > 3*10^5. _Robert Price_, Jul 10 2023
%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 k = 8 ==> 10^8+49 = 100000049, which is prime.
%t a={};Do[p=10^n+49;If[PrimeQ[p],AppendTo[a,n]],{n,0,10^3,1}];a (* _Vladimir Joseph Stephan Orlovsky_, Jul 17 2008 *)
%o (PARI) for(n=1,1e4,if(ispseudoprime(10^n+49),print1(n", "))) \\ _Charles R Greathouse IV_, Jul 25 2011
%Y Cf. A049054, A088274, A088275, A095688.
%K nonn,more
%O 1,2
%A Julien Peter Benney (jpbenney(AT)ftml.net), Jun 02 2005
%E a(23) from _Ray G. Opao_, Dec 13 2006
%E a(24)-a(31) from _Robert Price_, May 28 2010
%E Edited by _Ray Chandler_, Dec 23 2010
%E a(32) from _Robert Price_, Dec 27 2010
%E a(33) from _Robert Price_, Mar 03 2011
%E a(34)-a(37) from _Robert Price_, Jul 10 2023
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