sum*product = n
David W. Wilson
wilson at aprisma.com
Tue Dec 11 22:00:24 CET 2001
"Robert G. Wilson v" wrote:
>
> Et al,
>
> Using Mathematica, I have tested the sequence up to 7.5*10^7 and
> have found no further numbers which satisfy the criteria.
>
> Bob.
>
> "N. J. A. Sloane" wrote:
>
> > Sol Golomb recently mentioned an old puzzle:
> >
> > find all n such that sum of digits of n times
> > product of digits of n is equal to n
> >
> > this is a finite sequence which begins 1, 135, 144
> >
> > does any seq fan know of further terms?
> >
> > Neil
> >
> > e g (1+3+5)*1*3*5) = 135
Try again.
I showed that 1, 135, and 144 are all there are.
See "Sum-Product Numbers" at mathworld.com.
- Dave Wilson
Alzheimer's victim
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