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%I #14 Jan 13 2020 11:31:00
%S 1,3,4,6,7,12,17,28,46,75,105,309,351,460,774,785,2206,5739,12427,
%T 14501,17950,68331,106559,166996
%N Numbers k such that 9*10^k + 59 is prime.
%C For k > 1, numbers such that the digit 9 followed by k-2 occurrences of the digit 0 followed by the digits 59 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 90w59</a>,
%e 3 is in this sequence because 9*10^3 + 59 = 9059 is prime.
%e Initial terms and primes associated:
%e a(1) = 1, 149;
%e a(2) = 3, 9059;
%e a(3) = 4, 90059;
%e a(4) = 6, 9000059;
%e a(5) = 7, 90000059; etc.
%t Select[Range[0, 100000], PrimeQ[9*10^# + 59] &]
%Y Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.
%K nonn,more,hard
%O 1,2
%A _Robert Price_, Oct 06 2017
%E a(23)-a(24) from _Robert Price_, Jan 13 2020
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