emirp
English edit
Etymology edit
prime spelled backwards.
Noun edit
emirp (plural emirps)
- (number theory) A 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, ...
- 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, ...
- 1986, Malcolm E. Lines, A Number for your Thoughts, Taylor & Francis, page 39:
- 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.
Usage notes edit
- A palindromic prime is not considered an emirp.
- The term reversible prime is generally synonymous with emirp, but sometimes includes palindromic primes. (See
Emirp on Wikipedia.Wikipedia )
Further reading edit
- Emirp on Wikipedia.Wikipedia
- Permutable prime on Wikipedia.Wikipedia