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%I #9 Nov 17 2018 21:52:10
%S 3,2,3,3,6,2,3,6,3,11,7,2,70,2,22,18,43,3,4,649,15,3,37,2,24,13,4,8,
%T 40,77,19,22,13,24,292,48,4,2,109,792,30,4,18,5,7,90,28,138,132,891,9,
%U 25,145,2,24,9,40,28,219,165,40,41,4,13,261,24,6,30,6,154,82,22,120,2,55
%N Smallest k > 1 such that k^n followed by digit 1 is a prime.
%e a(4) = 3 as concatenation of 3^4 and 1 = 811 is a prime. 161 is not a prime.
%t Do[k = 2; While[ !PrimeQ[10*k^n + 1], k++ ]; Print[k], {n, 1, 30}] (* _Ryan Propper_, Jul 08 2005 *)
%Y Cf. A089318.
%K base,nonn
%O 1,1
%A _Amarnath Murthy_, Nov 03 2003
%E Corrected and extended by _Ryan Propper_, Jul 08 2005
%E Further terms from _David Wasserman_, Sep 09 2005
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