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%I #13 Mar 09 2020 09:12:46
%S 0,11,661,6661,11161,111611,1111661,11111161,111616111,1111161661,
%T 11111111611,111111111611,1111111111661,11111111616611,
%U 111111111116111,1111111111616161,11111111111611661,111111111111111161
%N Smallest n-digit prime containing only digits 1 and 6, or 0 if no such prime exists.
%H Jinyuan Wang, <a href="/A036933/b036933.txt">Table of n, a(n) for n = 1..500</a>
%t Join[{0},Flatten[Table[Select[Sort[FromDigits/@Tuples[{1,6},i]], PrimeQ, 1], {i,2,20}]]] (* _Harvey P. Dale_, May 06 2014 *)
%Y Cf. A020454, A036229, A036306.
%K nonn,base
%O 1,2
%A _Patrick De Geest_, Jan 04 1999