Sphenic number
From Wikipedia, the free encyclopedia.

A sphenic number is a number that has precisely three distinct prime factors. The Möbius function returns negative one when passed any sphenic number.

The first ten sphenic numbers are:

1. 30
2. 42
3. 66
4. 70
5. 78
6. 102
7. 105
8. 110
9. 114
10. 130

The original article can be found at: http://en.wikipedia.org/wiki/Sphenic_number.
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