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%I #15 Jun 01 2023 03:55:04
%S 0,1,2,3,4,5,6,10,24,33,34,35,45,52,56,62,65,103,166,424,886,1418,
%T 1825,4895,5715,7011,7810,9097,12773,14746,20085,25359,27967,46629,
%U 48507,68722,74944,102541,118960,157368
%N Numbers k such that (8*10^k + 49)/3 is prime.
%C For k>2, numbers such that the digit 2 followed by k-3 occurrences of the digit 6 followed by the digits 83 is prime (see Example section).
%C a(41) > 3*10^5.
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/primedifficulty.txt">Search for 26w83</a>.
%e 3 is in this sequence because (8*10^3 + 49)/3 = 2683 is prime.
%e Initial terms and primes associated:
%e a(1) = 0, 19;
%e a(2) = 1, 43;
%e a(3) = 2, 283;
%e a(4) = 3, 2683;
%e a(5) = 4, 26683;
%e a(6) = 5, 266683, etc.
%t Select[Range[0, 100000], PrimeQ[(8*10^# + 49)/3] &]
%o (PARI) is(n)=isprime((8*10^n + 49)/3) \\ _Charles R Greathouse IV_, Feb 16 2017
%Y Cf. A056654, A268448, A269303, A270339, A270613, A270831.
%K nonn,more
%O 1,3
%A _Robert Price_, Mar 25 2016
%E a(38)-a(40) from _Robert Price_, May 23 2020
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