I bumped into this today in the most recent issue of CMJ.

Divide 10000 by 9801, and carry it out to a couple hundred decimal places. (Don't want to do it by hand? Then use Mathematica, for example). You will be amazed at what you see.

And of course, 9801 is the reverse of 1089! I wonder if that could be exploited in an interesting way...

Thomas Henry

This can be extended:
Divide 1000000 by 998001.
Divide 100000000 by 99980001.


Prefer powers of two?
Divide 1 by 499999999.


Fibonacci?
Divide 1 by 999998999999.

This certainly is interesting...

Thomas Henry,

I don't get CMJ...and was surprised to find that my university library no
longer does either.

Found a professor who gets the journal. He let me flip through his most
recent issues...but I couldn't find anything related to the "attractive
number." Maybe you got the "newest" issue before he received his. Or
maybe I had the correct issue in hand, but flipped through it too
carelessly.

What is the issue vol/no that this appears in?

Thanks for the reference.

Stan

Hello Stan and other interested listeners,



I just knew someone was going to ask that, so brought the issue home with me this weekend. It's final exam week coming up and I'm busy as hell, but wanted to have this nearby just in case. Here's the dope:

_The College Mathematics Journal_, Volume 39, Number 3, May 2008, p. 211, with a quickie article by James Smoak. He mentions the Fibonacci version you reported, but not the powers-of-two version. Thanks for passing that on.

And to all others: the MAA has run quite a few mathematical magic things over the past couple of years in the Monthly, CMJ and the Mathematics Magazine. Check it out!

Thomas Henry

Thomas,

Your assistance is greatly appreciated!

Can't put my hands on my copy of _Concrete Mathematics_, but I recall
seeing some of this stuff in its pages.

I'll be visiting my library (and my friend's office) later today.

I hope I can provide references as detailed as those provided by
Thomas Henry. But until I get my hands on a copy of Concrete
Mathematics, the best I can do is point interested parties to
the book that I think contains related material:

http://www.amazon.com/Concrete-Mathemati......4&sr=8-1

Still waiting for May 2008 CMJ.
My university library doesn't have Concrete Mathematics...
and I can't locate my copy.

Stan