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A109661 Numbers n such that the sum of the digits of phi(n)^n is divisible by n. 0
1, 9, 18, 23, 45, 172, 578, 4788, 6039, 6408, 10303 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Next term after 6408 is greater than 10000.

LINKS

Table of n, a(n) for n=1..11.

EXAMPLE

The sum of the digits of phi(6039)^6039 is 42273 and 42273 is divisible by 6039, so 6039 is in the sequence.

MATHEMATICA

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

Select[Range[11000], Divisible[Total[IntegerDigits[EulerPhi[#]^#]], #]&] (* Harvey P. Dale, Oct 18 2014 *)

CROSSREFS

Sequence in context: A046412 A171081 A232056 * A015798 A028494 A167663

Adjacent sequences:  A109658 A109659 A109660 * A109662 A109663 A109664

KEYWORD

base,nonn

AUTHOR

Ryan Propper, Aug 06 2005

EXTENSIONS

a(11) from Stefan Steinerberger, Jan 24 2006

STATUS

approved

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Last modified November 21 22:35 EST 2019. Contains 329383 sequences. (Running on oeis4.)