%I #19 Jan 17 2019 13:44:07
%S 1,2,4,7,13,28,58,86,92,108,1408,1486,1712,2674,3880,5536,7588,7650,
%T 10558,15532,17959,37180,93082
%N Numbers n such that 9*10^n + 6*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
%C Also numbers n such that (29*10^n+1)/3 is prime.
%C a(24) > 10^5. - _Robert Price_, Nov 12 2015
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/9/96667.htm#prime">Prime numbers of the form 966...667</a>.
%H <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%F a(n) = A101013(n) + 1.
%t Do[ If[ PrimeQ[(29*10^n + 1)/3], Print[n]], {n, 0, 10000}]
%Y Cf. A002275, A101013.
%K more,nonn
%O 1,2
%A _Robert G. Wilson v_, Jan 19 2005
%E a(19)-a(21) from Kamada data by _Robert Price_, Dec 14 2010
%E a(22) from Erik Branger May 01 2013 by _Ray Chandler_, Aug 17 2013
%E a(23) from _Robert Price_, Nov 12 2015
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