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%I #13 Apr 04 2022 16:53:13
%S 0,1,4,6,9,10,16,31,33,93,289,304,921,1183,3946,4506,4978,5481,7114,
%T 13512,14703,14823,16851,26662,77377,82417,95316,98982,102000,139920
%N Numbers k such that 8*10^k + 51 is prime.
%C For k>1, numbers such that the digit 8 followed by k-2 occurrences of the digit 0 followed by the digits 51 is prime (see Example section).
%C a(31) > 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 80w51</a>.
%e 4 is in this sequence because 8*10^4 + 51 = 80051 is prime.
%e Initial terms and primes associated:
%e a(1) = 0, 59;
%e a(2) = 1, 131;
%e a(3) = 4, 80051;
%e a(4) = 6, 8000051;
%e a(5) = 9, 8000000051; etc.
%t Select[Range[0, 100000], PrimeQ[8*10^# + 51] &]
%Y Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.
%K nonn,more,hard
%O 1,3
%A _Robert Price_, May 22 2017
%E a(29)-a(30) from _Robert Price_, Aug 18 2019
%E Terms reordered into ascending order by _Robert Price_, Apr 03 2022
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