Fermat number
English edit
Etymology edit
Named after French lawyer and amateur mathematician Pierre de Fermat (1601–1665).
Noun edit
Fermat number (plural Fermat numbers)
- (number theory) An integer which is one more than two raised to a power which is itself a power of two (i.e., is expressible in the form for some ); equivalently, a number that is one more than two raised to some power (is expressible as ) and is prime.
- Hyponym: Fermat prime
Usage notes edit
The equivalence of the two definitions follows from the fact that, as can be demonstrated, for a number of the form to be prime it is necessary (though not sufficient) that for some .