login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A089692 a(n)=phi(2n)/2^omega(n). 0
1, 1, 1, 2, 2, 1, 3, 4, 3, 2, 5, 2, 6, 3, 2, 8, 8, 3, 9, 4, 3, 5, 11, 4, 10, 6, 9, 6, 14, 2, 15, 16, 5, 8, 6, 6, 18, 9, 6, 8, 20, 3, 21, 10, 6, 11, 23, 8, 21, 10, 8, 12, 26, 9, 10, 12, 9, 14, 29, 4, 30, 15, 9, 32, 12, 5, 33, 16, 11, 6, 35, 12, 36, 18, 10, 18, 15, 6, 39, 16, 27, 20, 41, 6, 16, 21 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Here omega(n) means the number of prime factors of n counted without multiplicity. - Harvey P. Dale, Dec 12 2012

LINKS

Table of n, a(n) for n=1..86.

FORMULA

a(n)=A062570(n)/A034444(n)

Multiplicative with a(2^e) = 2^(e-1) and a(p^e) = (p^e-p^(e-1))/2 for an odd prime p. - Vladeta Jovovic, Jan 15 2004

MATHEMATICA

Table[EulerPhi[2n]/2^PrimeNu[n], {n, 90}] (* Harvey P. Dale, Dec 12 2012 *)

CROSSREFS

Sequence in context: A105809 A091594 A118032 * A066201 A303273 A193820

Adjacent sequences:  A089689 A089690 A089691 * A089693 A089694 A089695

KEYWORD

nonn,mult

AUTHOR

Benoit Cloitre, Jan 06 2004

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 19 10:47 EST 2018. Contains 317349 sequences. (Running on oeis4.)