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%I #30 May 18 2019 17:42:53
%S 0,2,3,5,6,11,15,36,38,339,608,699,1554,3984,4281,7599,12461,13697,
%T 13826,16431,39108,43239,46685,103046
%N Numbers k such that (58*10^k + 419)/9 is prime.
%C For k>1, numbers such that the digit 6 followed by k-2 occurrences of the digit 4 followed by the digits 91 is prime (see Example section).
%C a(25) > 2*10^5.
%H Makoto Kamada, <a href="https://stdkmd.net/nrr">Factorization of near-repdigit-related numbers</a>.
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/primedifficulty.txt">Search for 64w91</a>.
%e 2 is in this sequence because (58*10^2 + 419)/9 = 691 is prime.
%e Initial terms and primes associated:
%e a(1) = 0, 53;
%e a(2) = 2, 691;
%e a(3) = 3, 6491;
%e a(4) = 5, 644491;
%e a(5) = 6, 6444491; etc.
%t Select[Range[0, 100000], PrimeQ[(58*10^# + 419)/9] &]
%Y Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.
%K nonn,more,hard
%O 1,2
%A _Robert Price_, Nov 05 2017
%E a(24) from _Robert Price_, May 18 2019
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