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%I #8 Aug 18 2015 12:27:32
%S 1,1,9,7,3,3,37,7,7,19,3,37,31,37,61,13,3,3,39,139,57,9,49,7,67,331,
%T 319,211,57,33,49,61,103,69,67,43,321,37,3,169,63,57,31,121,9,33,217,
%U 69,9,327,171,157,31,21,279,3,193,19,67,7,121,399,57,49,49,49
%N Smallest k such that 1000...0//k (concatenation of 10^n and k) is prime.
%H Felix Fröhlich, <a href="/A260880/b260880.txt">Table of n, a(n) for n = 0..1000</a>
%e The smallest prime whose decimal expansion starts with 10^6 = 1000000 is 100000037, so a(6) = 37.
%o (PARI) a(n) = my(k=1); while(!ispseudoprime(eval(Str(10^n, k))), k++); k
%Y Similar to but different from A033873.
%K nonn,base
%O 0,3
%A _Felix Fröhlich_, Aug 02 2015
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