A055679 Number of distinct prime factors of phi(n!).
0, 0, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14
Offset: 1
Links
- G. C. Greubel, Table of n, a(n) for n = 1..5000
Programs
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Mathematica
PrimeNu[EulerPhi[Range[90]!]] (* Harvey P. Dale, Sep 27 2011 *)
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PARI
for(n=1,50, print1(omega(eulerphi(n!)), ", ")) \\ G. C. Greubel, May 19 2017
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PARI
a(n) = primepi(n\2); \\ Michel Marcus, Aug 13 2024
Comments