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%I #27 Feb 01 2023 19:57:03
%S 3,5,9,29,65,725,1787,7277,19463,24215,51779,131393
%N Numbers k such that (65*10^(k-1) + 43)/9 is a depression prime.
%C Prime versus probable prime status and proofs are given in the author's table.
%C a(13) > 2*10^5. - _Tyler Busby_, Feb 01 2023
%D C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
%H Patrick De Geest, <a href="http://www.worldofnumbers.com/deplat.htm#pdp727">PDP Reference Table - 727</a>.
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/7/72227.htm#prime">Prime numbers of the form 722...227</a>.
%H <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%F a(n) = A056257(n) + 2.
%e k=9 -> (65*10^(9-1) + 43)/9 = 722222227.
%Y Cf. A082697-A082720, A056257.
%K nonn,base,hard,more
%O 1,1
%A _Patrick De Geest_, Apr 13 2003
%E Update from De Geest site by Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
%E a(11)=51779 from _Ray Chandler_, Nov 16 2010
%E Edited by _Ray Chandler_, Nov 05 2014
%E a(12) from _Tyler Busby_, Feb 01 2023