Definition:Sphenic Number

From ProofWiki
Jump to navigation Jump to search


A sphenic number is a (positive) integer which has exactly $3$ distinct prime factors all with multiplicity of $1$.

Sequence of Sphenic Numbers

The sequence of sphenic numbers begins:

$30, 42, 66, 70, 78, 102, 105, 110, 114, \ldots$

This sequence is A007304 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).

Linguistic Note

The term sphenic number derives from the ancient Greek σφήνα meaning wedge.

It is pronounced with a long e: sfee-nic, to rhyme with the English word scenic.