emirp

plural emirps

1. mathematicsA prime number that becomes a different prime when its decimal digits (or digits in some specified other base) are reversed.

   The sequence of emirps begins: 13, 17, 31, 37, 71, 73, 79, 97, 107, ...

   2 more examples

   The first few emirps in base 12 (using the convention T for ten and E for eleven) are: 15, 51, 57, 5E, 75, E5, 107, ...

   Therefore we do not yet know whether the general emirps go on forever or whether they too eventually end with a largest emirp of all.

   1986, Malcolm E. Lines, A Number for your Thoughts, Taylor & Francis, page 39