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Smallest prime obtained as a concatenation of n and a number m greater than n.
3

%I #7 Dec 05 2013 19:55:18

%S 13,23,37,47,59,67,79,89,911,1013,1117,1213,1319,1423,1523,1619,1721,

%T 1823,1931,2027,2129,2237,2333,2437,2531,2633,2729,2833,2939,3037,

%U 3137,3251,3343,3449,3539,3637,3739,3847,3943,4049,4153,4243,4349,4447,4547

%N Smallest prime obtained as a concatenation of n and a number m greater than n.

%C If we change the definition to m >= n, then a(1) becomes 11, but nothing else changes.

%C Conjectures: There is at least one number k with n<k<2n such that the concatenation n and n+k is a prime. For all m there is at least one number k with m*n < k < (m+1)*n such that the concatenation n and n+k is a prime.

%Y Cf. A089713, A089715.

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Nov 17 2003

%E Edited by _David Wasserman_, Feb 05 2004

%E Further edited by _N. J. A. Sloane_, Oct 21 2008 at the suggestion of R. J. Mathar