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%I #9 Jan 17 2019 13:44:08
%S 1,2,3,9,17,18,20,24,29,36,48,114,126,135,153,170,241,363,483,579,681,
%T 948,2483,2798,3081,5137,5640,6890,7080,12600,16929,24253,24793,35546,
%U 52956,69645,133831
%N Numbers k such that (11*10^k + 19)/3 is prime.
%C For k>1, numbers such that the digit 3 followed by k-2 occurrences of the digit 6 followed by the digits 73 is prime (see Example section).
%C a(38) > 2*10^5.
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/primedifficulty.txt">Search for 36w73.</a>
%e 3 is in this sequence because (11*10^3 + 19)/3 = 3673 is prime.
%e Initial terms and primes associated:
%e a(1) = 1, 43;
%e a(2) = 2, 373;
%e a(3) = 3, 3673;
%e a(4) = 9, 3666666673;
%e a(5) = 17, 366666666666666673, etc.
%t Select[Range[0, 100000], PrimeQ[(11*10^# + 19)/3] &]
%o (PARI) is(n)=isprime((11*10^n + 19)/3) \\ _Charles R Greathouse IV_, Mar 16 2016
%Y Cf. A056654, A268448, A269303.
%K nonn,more
%O 1,2
%A _Robert Price_, Mar 15 2016
%E a(37) from _Robert Price_, Sep 16 2018
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