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%I #5 Dec 05 2013 19:56:37
%S 3,1,2,1,3,3,1,2,1,6,1,1,2,5,3,1,1,5,1,5,1,3,4,1,2,4,5,22,1,6,3,2,1,3,
%T 1,1,2,4,3,14,12,15,4,3,4,1,1,1,2,14,3,4,1,3,1,8,1,4,5,6,3,4,14,1,1,5,
%U 3,3,2,6,1,3,26,2,6,1,7,2,3,21,1,3,2,6,3,2,9,10,4,3,15,9,4,7,5,1,3,5,5,5,16
%N Least positive r such that concatenation k, r, k is prime, where k == 1,3,7 or 9 (mod 10) in increasing order.
%e 131,313,727,919,11311,... etc. are primes.
%Y Cf. A090271.
%K base,nonn
%O 1,1
%A _Amarnath Murthy_, Nov 28 2003
%E More terms from _Joshua Zucker_, May 03 2006
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