A109668 Numbers n such that the sum of the digits of phi(n)^sigma(n) is divisible by n.

1, 9, 18, 35, 67, 189, 310, 475, 516, 684, 2493, 2527, 3465, 4701, 5157, 8321, 11403, 11780, 14709, 18396, 47250, 124385, 131952, 280342, 288820, 304299, 525195, 536756, 899703

Offset

1,2

Links

Table of n, a(n) for n=1..29.

Example

The digits of phi(3465)^sigma(3465) sum to 72765 and 72765 is divisible by 3465, so 3465 is in the sequence.

Mathematica

Do[s = EulerPhi[n]^DivisorSigma[1, n]; k = Plus @@ IntegerDigits[s]; If[Mod[k, n] == 0, Print[n]], {n, 1, 10^4}]
Select[Range[50000], Divisible[Total[IntegerDigits[EulerPhi[#]^ DivisorSigma[1, #]]], #]&] (* Harvey P. Dale, Mar 19 2011 *)

Crossrefs

Sequence in context: A221533 A139591 A191268 * A234598 A051063 A173942

Adjacent sequences: A109665 A109666 A109667 * A109669 A109670 A109671

Keyword

base,more,nonn

Author

Ryan Propper, Aug 06 2005

Extensions

More terms from Harvey P. Dale, Mar 19 2011

a(22)-a(29) from Lars Blomberg, Dec 02 2016

Status

approved