[Nottingham] A numerical puzzle & "mathomatic"

Richard Ward daedalusfall at gmail.com
Mon Jan 18 18:33:46 UTC 2010

Martin wrote:
> Camilo Mesias wrote:
>> It doesn't need that much brute force because the equation is so
>> limited. The a+b+c bit appears twice and they are single digits. If n
>> is a+b+c we can figure n is between 0 and 27, and n^2 + n is a three
>> digit number. We have to start at n=10 to get a three digit result
>> (110) but those digits don't add up to 10...
>> n=11 (132)...
>> n=12 (156) bingo
>> just as well because my times tables run out there!
> Very good and well deduced.
> Thinking further about trying for an algebra solution... There isn't one
> in that all that any manipulation can do is either rearrange the formula
> or just prove an identity.
> At least it prompted a brief look at the "Mathomatic" program which
> turned out to be rather neat. Hope I haven't spoilt anyone's homework!
> Thanks for that,
> Cheers,
> Martin

Everyone likes a good maths puzzle, right?
The new scientist has one every week. They are mostly fun combinatorics 
problems which can be solved in a few elegant lines of python (or your 
favorite language). I discovered the wonderful 'bc' because of this. 
Just try:
echo 9^99999|bc
Its so fast! And supports scripting in a language a little like c.

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