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%I #7 Dec 05 2013 19:56:32
%S 1,1,0,1,4,0,2,1,0,1,4,0,37,7,0,17,149,0,185,7,0,73,1,0,5,47,0,38,4,0,
%T 4,133,0,52,2,0,194,46,0,37,29,0,29,25,0,19,14,0,74,8,0,19,20,0,442,
%U 83,0,358,211,0,16,298,0,260,5,0,305,71,0,8,323,0,5,109,0,8,68,0,767,367
%N Smallest k such that n times concatenation of k with itself followed by a 3 is a prime, or 0 if no such number exists.
%C Trivially a(3n) = 0. Conjecture: no other term is zero.
%C Either a(13)=0 or a(13)>36. This sequence contains no positive multiples of 3. If a(m) is of the form bbb...b (repeated k times) then a(km) <= b. - _Sam Alexander_, Oct 20 2003
%e a(5) = 4 as 444443 is a prime. but 111113,222223,333333 are not.
%Y Cf. A086920, A087605, A087606, A087607, A087608, A087609, A087610.
%K base,nonn
%O 1,5
%A _Amarnath Murthy_, Sep 18 2003
%E More terms from _Sam Alexander_, Oct 20 2003
%E More terms from _Ray G. Opao_, Apr 15 2004
%E More terms from _David Wasserman_, Jun 16 2005
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