%I A036229
%S A036229 2,11,211,2111,12211,111121,1111211,11221211,111112121,1111111121,
%T A036229 11111121121,111111211111,1111111121221,11111111112221,
%U A036229 111111112111121,1111111112122111,11111111111112121,111111111111112111,
               1111111111111111111
%N A036229 Smallest n-digit prime containing only digits 1 and 2.
%C A036229 It is conjectured that such a prime always exists.
%C A036229 a(2), a(19), a(23), etc. are the prime repunits (A004023). a(1000) = 
               (10^n-1)/9 + 111011000010.
%H A036229 Robert G. Wilson v, <a href="a036229.txt">Comments and first 100 terms</
               a>
%t A036229 Do[p = (10^n - 1)/9; k = 0; While[ ! PrimeQ[p], k++; p = FromDigits[ 
               PadLeft[ IntegerDigits[k, 2], n] + 1]]; Print[p], {n, 1, 20}]
%Y A036229 Cf. A036937, A068086.
%Y A036229 Sequence in context: A051663 A070256 A020450 this_sequence A104337 A042805 
               A088639
%Y A036229 Adjacent sequences: A036226 A036227 A036228 this_sequence A036230 A036231 
               A036232
%K A036229 nonn,base,nice
%O A036229 1,1
%A A036229 G. L. Honaker, Jr. (honak3r(AT)gmail.com)
%E A036229 Edited by N. J. A. Sloane (njas(AT)research.att.com) and Robert G. Wilson 
               v (rgwv(AT)rgwv.com), May 03 2002