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A329121 Smallest k such that m//A002275(n)//m is prime, where // denotes concatenation, A002275(n) is the n-th repunit (R_n) and m = k+10^(A006519(n)-1).

%I A329121 #18 Nov 24 2019 19:00:15
%S A329121 0,2,3,16,73,18,7,28,117,72,7,2,7,2,33,10,29,0,21,10,191,0,1133,30,79,
%T A329121 20,81,58,19,2,57,116,77,108,79,48,97,40,1043,42,47,86,13,52,149,82,
%U A329121 47,56,9,80,41,42,61,86,51,68,311,262,1001,222,7,496,1367,12
%N A329121 Smallest k such that m//A002275(n)//m is prime, where // denotes concatenation, A002275(n) is the n-th repunit (R_n) and m = k+10^(A006519(n)-1).
%C A329121 a(n) = A263182(n) - 10^(A006519(n)-1). We use the convention that A007814(0) = 0 and A006519(0) = 1.
%C A329121 a(A004023(n)-2) = 0.
%H A329121 Chai Wah Wu, <a href="/A329121/b329121.txt">Table of n, a(n) for n = 0..5007</a>
%Y A329121 Cf. A002275, A004023, A006519, A007814, A263182.
%K A329121 nonn,base
%O A329121 0,2
%A A329121 _Chai Wah Wu_, Nov 05 2019