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A053574
Exponent of 2 in phi(n) where phi(n) = A000010(n).
9
0, 0, 1, 1, 2, 1, 1, 2, 1, 2, 1, 2, 2, 1, 3, 3, 4, 1, 1, 3, 2, 1, 1, 3, 2, 2, 1, 2, 2, 3, 1, 4, 2, 4, 3, 2, 2, 1, 3, 4, 3, 2, 1, 2, 3, 1, 1, 4, 1, 2, 5, 3, 2, 1, 3, 3, 2, 2, 1, 4, 2, 1, 2, 5, 4, 2, 1, 5, 2, 3, 1, 3, 3, 2, 3, 2, 2, 3, 1, 5, 1, 3, 1, 3, 6, 1, 3, 3, 3, 3, 3, 2, 2, 1, 3, 5, 5, 1, 2, 3, 2, 5, 1, 4, 4, 2, 1, 2, 2, 3, 3, 4, 4, 2, 3, 3, 3, 1, 5, 5
OFFSET
1,5
LINKS
FORMULA
a(n) = A007814(A000010(n)).
A000010(n) = A053575(n) * 2^a(n). - Antti Karttunen, May 26 2017
Additive with a(2^e) = e-1, and a(p^e) = A007814(p-1) for an odd prime p. - Amiram Eldar, Sep 05 2023
EXAMPLE
For n = 513 = 27*19, phi(513) = 4*81 so exponent of 2 is 2, thus a(513) = 2.
MATHEMATICA
IntegerExponent[Array[EulerPhi, 120], 2] (* Michael De Vlieger, Aug 16 2017 *)
PROG
(PARI) vector(66, n, valuation(eulerphi(n), 2)) \\ Joerg Arndt, Apr 22 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Labos Elemer, Jan 18 2000
EXTENSIONS
Data section extended to 120 terms by Antti Karttunen, May 26 2017
STATUS
approved