Definition:Sphenic Number
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Definition
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.
Sources
- Stover, Christopher and Weisstein, Eric W. "Sphenic Number." From MathWorld--A Wolfram Web Resource, created by Eric W. Weisstein. https://mathworld.wolfram.com/SphenicNumber.html