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%I #12 Aug 02 2015 16:44:31
%S 2,10,12,18,44,60,88,108,110,114,116,122,192,198,282,380,446,574,588,
%T 604,612,618,838,840,864,970,1032,1068,1104,1148,1186,1228,1258,1314,
%U 1368,1384,1390,1412,1754,1888,1894,1930,2658,2660,2728,2784,2804
%N Numbers n such that n^2 + 13 is an emirp.
%C A decimal emirp/mirp ("prime" / (German) "prim", spelled backwards) is defined as a prime number p whose reversal R(p) is also prime, but which is not a palindromic prime.
%D W. W. R. Ball, H. S. M. Coxeter: Mathematical Recreations and Essays, 13th edition, Dover Publications, 2010
%D H. Steinhaus: Kaleidoskop der Mathematik, VEB Dt. Verl. d. Wissenschaften, Berlin, 1959
%H Vincenzo Librandi, <a href="/A178504/b178504.txt">Table of n, a(n) for n = 1..8000</a>
%e 2^2 + 13 = 17 = prime(7), 71 = prime(20), so 2 is in the sequence.
%e 10^2 + 13 = 113 = prime(30), 311 = prime(64), so 10 is in the sequence.
%e 28^2 + 13 = 797, which is a palindromic prime, so 28 is not in the sequence.
%t fQ[n_] := If[ PrimeQ[n^2 + 13], Block[{id = IntegerDigits[n^2 + 13]}, rid = Reverse@ id; PrimeQ@ FromDigits@ rid && rid != id]]; Select[ Range@ 3000, fQ] (* _Robert G. Wilson v_, Jul 26 2010 *)
%Y Subsequence of A113536.
%Y Cf. A138375, A176978, A178044.
%K base,nonn
%O 1,1
%A Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), May 29 2010
%E More terms from _Robert G. Wilson v_, Jul 26 2010