Writing an integer as the sum of powers of phi

[BSMSMSTMSPHD]

A while back, I found an online applet that was located on the front page of the mathematics department website for some American university. The problem is that I can't remember which university it was, and I'm not succeeding in several searches.

Basically, the way it worked was, you type in any integer, and it produces the exponents of phi that sum to your number. For example, if the number was 521, the exponents would be -12, -10, -8, -6, -4, -2, 0, 2, 4, 6, 8, 10, 12 (which is a nice little pattern...)

Anyway - does anyone know what I'm talking about? Do you know the website I'm referring to? It's quite possible that it has been taken down...

Failing this, is there any method you know of doing this by hand?

Thanks!

 

[CRGreathouse]

Here's a website with an explanation of how to do it (by hand, no applets):
http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/phigits.html

 

[BSMSMSTMSPHD]

Thanks! I had disregarded this site since I found it so hard to read. But, upon finding no other sites, I tried again, and it actually makes a lot of sense.