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The X-Philes (2nd Revision)
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The X-Philes Number 1 (1995).iso
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hp48hor2
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phi.doc
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1995-03-31
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PHI by Joseph K. Horn -- A Number Theory tool.
Calculates PHI(x), Euler's totient function.
+-------------------------------------------------------------------------+
| NOTE: This program calls FACTOR, a program by Jurjen NE Bos, available |
| on EduCALC Goodies Disk #2. You must be in the FACTOR directory when |
| you upload ALLF, or it will not work. |
+-------------------------------------------------------------------------+
PHI(x) is defined as the number of integers between 1 and x that are
relatively prime to x (i.e. share no prime factors with x).
For example, since 15 is relatively prime to 1, 2, 4, 7, 8, 11, 13 and
14 (8 numbers), PHI(15) is 8.
By convention, 1 is neither a prime nor a composite, and is therefore
considered relatively prime to everything. Thus PHI(1)=1.
PHI of anything less than 1 yields 0.
The number of primitive roots of x is exactly equal to PHI(PHI(x)). For
example, to see that 351 has 72 primitive roots, type 351 and press PHI
twice. This means that there are 72 numbers between 1 and 351 which are
relatively prime to 351. Anything that can be described in terms of
close-range random but long-range patterns can be modeled by primitive
root cycles. The applications of this range from the SpiroGraph child's
toy to the mathematics of Chaos Theory.
-Joseph K. Horn- -Peripheral Vision, Ltd.-