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%I #10 Mar 22 2020 23:43:15
%S 0,1,3,4,12,16,27,39,190,192,327,378,444,958,1779,2809,3396,3844,4441,
%T 4452,9324,29007,29464,99303,100827,106618,107505
%N Numbers k such that (746*10^k + 1)/9 is prime.
%C For k>0, numbers such that the digits 82 followed by k-1 occurrences of the digit 8 followed by the digit 9 is prime (see Example section).
%C a(28) > 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 828w9</a>.
%e 3 is in this sequence because (746*10^3 + 1)/9 = 82889 is prime.
%e Initial terms and primes associated:
%e a(1) = 0, 83;
%e a(2) = 1, 829;
%e a(3) = 3, 82889;
%e a(4) = 4, 828889;
%e a(5) = 12, 82888888888889; etc.
%t Select[Range[0, 100000], PrimeQ[(746*10^# + 1)/9] &]
%Y Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.
%K nonn,more,hard
%O 1,3
%A _Robert Price_, Feb 15 2017
%E a(25)-a(27) from _Robert Price_, Mar 22 2020
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