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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A109660 Numbers n such that the sum of the digits of n^phi(n) is divisible by n. 0

%I

%S 1,2,3,7,9,15,18,27,52,72,261,360,400,3932,4418,7046,7938,8888,9162,

%T 9363,9606,9738,10083,10809,11970,13958,23571,28384,42159,51515

%N Numbers n such that the sum of the digits of n^phi(n) is divisible by n.

%e The digits of 8888^phi(8888) sum to 71104 and 71104 is divisible by 8888, so 8888 is in the sequence.

%t Do[s = n^EulerPhi[n]; k = Plus @@ IntegerDigits[s]; If[Mod[k, n] == 0, Print[n]], {n, 1, 10000}]

%K base,nonn

%O 1,2

%A _Ryan Propper_, Aug 06 2005

%E More terms from _Emeric Deutsch_, Feb 05 2006

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 December 6 21:45 EST 2019. Contains 329809 sequences. (Running on oeis4.)