LOGO-L> Factorials

[Yehuda Katz <yehuka@beitberl.beitberl.ac.il>]

Hi,

Many years ago, using BASIC, we encountered the following problem:
Find all 3-digit numbers, that equal the sum of the factorials of their
digits.
In other words: We need all 3-digit numbers of the form ABC which
maintain: ABC=A!+B!+C!

I wanted to test UCBLogo to see how good it solves that problem. 
Here's one possible solution:

========================================
to solve
for[num 100 999][
    if equalp :num(sum fact item 1 :num
                       fact item 2 :num
                       fact item 3 :num)
    [pr :num]]
end

to fact :n
op ifelse :n<2[1][:n*fact :n-1]
end
========================================

The above solution is quite fast: It took some 9 seconds on P-120.
Next week I'll get my new P-266 machine. How faster is it? We wait and
see.

Regards...

[[Yehuda]]

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