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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A070809 Cototient(totient(n))=A070556(n) is not a power of 2 and n is not a prime number. 2
1, 22, 25, 27, 33, 38, 44, 46, 49, 50, 54, 55, 57, 62, 63, 66, 69, 74, 75, 76, 77, 81, 82, 86, 88, 91, 92, 93, 94, 95, 98, 99, 100, 106, 108, 110, 111, 114, 115, 117, 118, 121, 122, 123, 124, 125, 126, 129, 132, 133, 134, 135, 138, 141, 142, 143, 146, 147, 148 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..59.

EXAMPLE

n=95: Phi[95]=72,cototient[72]=72-phi[72]=72-24-=48 is not a power of 2.

MATHEMATICA

Do[s= EulerPhi[n]-EulerPhi[EulerPhi[n]]; If[ !IntegerQ[Log[2, s]]&&!PrimeQ[n], Print[n]], {n, 1, 1000}]

CROSSREFS

Cf. A070556, A051953, A054571, A070806, A070807, A070810, A070811.

Sequence in context: A092631 A061371 A254753 * A280646 A295799 A322124

Adjacent sequences:  A070806 A070807 A070808 * A070810 A070811 A070812

KEYWORD

nonn

AUTHOR

Labos Elemer, May 08 2002

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 13 17:34 EST 2019. Contains 329106 sequences. (Running on oeis4.)