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Smallest nontrivial extension of n-th palindromic prime which is a prime.
1

%I #11 May 24 2016 23:52:45

%S 23,31,53,71,113,1013,1319,1511,1811,1913,3137,3533,3733,3833,72701,

%T 7573,7873,79757,9199,9293,1030111,105019,106013,113111,114113,124213,

%U 127217,128213,133319,138311,139313,143413,147419,1545101,1555111,160619,163613,165611

%N Smallest nontrivial extension of n-th palindromic prime which is a prime.

%H Chai Wah Wu, <a href="/A030680/b030680.txt">Table of n, a(n) for n = 1..10000</a>

%t d[n_]:=IntegerDigits[n]; Table[i=1; While[!PrimeQ[x=FromDigits[Flatten[{d[n],d[i]}]]],i=i+2]; x,{n,Select[Prime[Range[2000]],Reverse[x=d[#]]==x &]}] (* _Jayanta Basu_, May 24 2013 *)

%K nonn,base

%O 1,1

%A _Patrick De Geest_

%E a(15) and a(34) corrected by _Chai Wah Wu_, May 24 2016