login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A074786 Numbers k such that phi(k) = Sum_{d|k} core(d) where core(x) is the squarefree part of x (A007913). 1

%I #16 Feb 14 2021 13:00:16

%S 1,99,1080,1836,4743,5670,7644,8307,14384,14784,15225,15824,16065,

%T 20300,21584,25704,29760,34544,46816,71568,94240,128412,169290,264160,

%U 266266,312480,331731,364941,404550,445050,454575,458052,479655,497781

%N Numbers k such that phi(k) = Sum_{d|k} core(d) where core(x) is the squarefree part of x (A007913).

%H Donovan Johnson, <a href="/A074786/b074786.txt">Table of n, a(n) for n = 1..500</a>

%o (PARI) isok(n) = eulerphi(n) == sumdiv(n, d, core(d)); \\ _Michel Marcus_, Aug 09 2013

%K nonn

%O 1,2

%A _Benoit Cloitre_, Sep 07 2002

%E More terms from _Michel Marcus_, Aug 09 2013

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 26 09:41 EST 2024. Contains 370338 sequences. (Running on oeis4.)