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%I #16 Feb 19 2020 11:19:47
%S 0,1,3,5,7,11,14,20,25,35,36,117,164,372,453,649,1743,1748,1897,2323,
%T 6351,16599,25017,25736,27866
%N Numbers k such that 34*10^k - 3 is prime.
%C For k>0, numbers such that the digits 33 followed by k-1 occurrences of the digit 9 followed by the digit 7 is prime (see Example section).
%C a(26) > 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 339w7</a>.
%e 3 is in this sequence because 34*10^3 - 3 = 33997 is prime.
%e Initial terms and primes associated:
%e a(1) = 0, 31;
%e a(2) = 1, 337;
%e a(3) = 3, 33997;
%e a(4) = 5, 3399997;
%e a(5) = 7, 339999997; etc.
%t Select[Range[0, 100000], PrimeQ[34*10^# - 3] &]
%Y Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.
%K nonn,more,hard
%O 1,3
%A _Robert Price_, Feb 21 2017
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