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%I #10 May 17 2019 17:17:43
%S 1,2,5,7,8,11,16,29,73,169,212,227,262,547,863,1325,2035,4808,8405,
%T 13612,16687,19456,122501
%N Numbers k such that (19*10^k + 149)/3 is prime.
%C For k>1, numbers such that the digit 6 followed by k-2 occurrences of the digit 3 followed by the digits 83 is prime (see Example section).
%C a(24) > 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 63w83</a>.
%e 5 is in this sequence because (19*10^5+149)/3 = 633383 is prime.
%e Initial terms and primes associated:
%e a(1) = 1, 113;
%e a(2) = 2, 683;
%e a(3) = 5, 633383;
%e a(4) = 7, 63333383;
%e a(5) = 8, 633333383; etc.
%t Select[Range[0, 100000], PrimeQ[(19*10^# + 149)/3] &]
%Y Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.
%K nonn,more,hard
%O 1,2
%A _Robert Price_, Apr 29 2017
%E a(23) from _Robert Price_, May 17 2019
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