OFFSET
1,1
COMMENTS
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.
REFERENCES
W. W. R. Ball, H. S. M. Coxeter: Mathematical Recreations and Essays, 13th edition, Dover Publications, 2010
H. Steinhaus: Kaleidoskop der Mathematik, VEB Dt. Verl. d. Wissenschaften, Berlin, 1959
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..8000
EXAMPLE
2^2 + 13 = 17 = prime(7), 71 = prime(20), so 2 is in the sequence.
10^2 + 13 = 113 = prime(30), 311 = prime(64), so 10 is in the sequence.
28^2 + 13 = 797, which is a palindromic prime, so 28 is not in the sequence.
MATHEMATICA
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 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), May 29 2010
EXTENSIONS
More terms from Robert G. Wilson v, Jul 26 2010
STATUS
approved