Counting Certain Coprime Integers

Leroy Quet qqquet at
Tue Nov 12 01:44:46 CET 2002

Just posted this to sci.math:

Let phi(m,k) = 
the number of positive integers j, where j <= m,
and GCD(j,k) = 1.
(So, phi(k,k) = phi(k), the standard Euler phi function.)

(Note: "phi(m,k)" here has NOT the same meaning as it does in another
recent post of mine to sci.math.)


For a given positive integer m, how many positive integers, k, are
there where:

phi(m,k) = k ?

I THINK the sequence begins (figured by hand):
1, 0, 1, 2, 0, 1, 1, 2, 0, 0,....

I know not how to calculate this sequence directly.

Leroy Quet

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