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Smallest n-digit prime containing only digits 1 and 8, or 0 if no such prime exists.
1

%I #9 Mar 09 2020 10:26:39

%S 0,11,181,1181,18181,0,1111181,11818181,111111181,1111111181,

%T 11111188811,0,1111111118111,11111111818181,111111111111881,

%U 1111111111111181,11111111111188111,0,1111111111111111111

%N Smallest n-digit prime containing only digits 1 and 8, or 0 if no such prime exists.

%C a(6k) = 0 as any 6k-digit number containing only digits 1 or 8 is divisible by 7. - _Jinyuan Wang_, Mar 09 2020

%H Jinyuan Wang, <a href="/A036935/b036935.txt">Table of n, a(n) for n = 1..500</a>

%Y Cf. A020456, A036229, A036308.

%K nonn,base

%O 1,2

%A _Patrick De Geest_, Jan 04 1999