|
| |
|
|
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
| 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: A000722 A098679 A123851 * A068943 A100815 A159932
Adjacent sequences: A120119 A120120 A120121 * A120123 A120124 A120125
|
|
|
KEYWORD
| base,fini,nonn
|
|
|
AUTHOR
| Farideh Firoozbakht (mymontain(AT)yahoo.com), Aug 12 2006
|
| |
|
|
