

A120122


Numbers n such that n=phi(d_1*d_2*...*d_k)*(d_1+d_2+...+d_k) where d_1 d_2... d_k is the decimal expansion of n.


2




OFFSET

1,2


COMMENTS

Conjecture: 139968 is the largest term. Except for the first term all terms are even. 139968 is also in the sequences A120121 & A120123, so it has a very pleasant property (see the Comments lines of A120121).


LINKS

Table of n, a(n) for n=1..4.
Prime Curios, 139968.


EXAMPLE

24 is in the sequence because 24=phi(2*4)*(2+4).


MATHEMATICA

Do[If[h = IntegerDigits[n]; l = Length[h]; n == EulerPhi[ Product[h[[k]], {k, l}]]*Sum[h[[k]], {k, l}], Print[n]], {n, 100000000}]


CROSSREFS

Cf. A120121, A120123.
Sequence in context: A098679 A123851 A258824 * A068943 A100815 A159932
Adjacent sequences: A120119 A120120 A120121 * A120123 A120124 A120125


KEYWORD

base,fini,nonn


AUTHOR

Farideh Firoozbakht, Aug 12 2006


STATUS

approved



