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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A196200 Numbers such that Euler Phi(Dedekind Psi(n)) > n. 1
39270, 53130, 71610, 78540, 82110, 106260, 108570, 117810, 122430, 143220, 157080, 159390, 164010, 164220, 212520, 214830, 217140, 235620, 244860, 246330, 247170, 286440, 293370, 314160, 318780, 325710, 328020, 328440, 353430, 367290, 425040, 429660, 434280 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Counterexamples to a conjecture by Sandor.

LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..66 (terms < 1000000)

Jozsef Sandor, On the Composition of Some Arithmetic Functions, II, Journal of Inequalities in Pure and Applied Mathematics (JIPAM), Volume 6, Issue 3, Article 73, 2005

MATHEMATICA

Select[Range[39270, 434280], EulerPhi[# * Sum[MoebiusMu[d]^2 / d, {d, Divisors[#]}]] > # &] (* Indranil Ghosh, Mar 11 2017 *)

PROG

(PARI) a(m) = {for (n=1, m, if (eulerphi(n * sumdiv( n, d, moebius(d)^2 / d)) > n, print1(n, ", ")); ); }

CROSSREFS

Cf. A000010, A001615.

Sequence in context: A233955 A250515 A031667 * A274128 A144306 A234033

Adjacent sequences:  A196197 A196198 A196199 * A196201 A196202 A196203

KEYWORD

nonn

AUTHOR

Michel Marcus, Dec 21 2012

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 April 22 10:24 EDT 2019. Contains 322330 sequences. (Running on oeis4.)