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For n > 1, a(n) is the smallest number such that n-th concatenation is prime and the smallest palindrome beginning with (but not equal to) this concatenation is also prime.
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%I #6 Dec 05 2013 19:56:33

%S 1,3,9,13,17,271,671,489,193,819,2219,5719,5753,2391,20089,3059,231,

%T 8259,16719,18493,37967,16197,8979,28153,11583,10073,14169,57589,

%U 85073,79053,121009,148997,69921,42033,12027,16437,20743,57363,240183,88689

%N For n > 1, a(n) is the smallest number such that n-th concatenation is prime and the smallest palindrome beginning with (but not equal to) this concatenation is also prime.

%C Conjecture: sequence is finite.

%e 11, (13 and 131), (139, 13931), (13913 and 139131931), etc. are all prime.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Sep 23 2003

%E More terms from _David Wasserman_, Jul 15 2005