Tuesday, May 08, 2007

Perfect numbers

A perfect number is one which equals the sum of all the numbers which can divide into it eg 6 is divisible by 3,2 and 1 and is also the sum of 3,2 and 1. The second perfect number is 28 (1, 2, 4, 7 and 14) and the next two are 496 and 8128. These were all known to the ancient Greeks but the fifth one was not discovered for another 1700 years which is not surprising considering its size: 33,550,336. As far as I know 37 perfect numbers have now been discovered and they are all even numbers.

6 Comments:

Blogger kinglear said...

At the risk of being sexist, I think the perfect numbers are 38-29-36. That's a good looking man in my book

4:15 pm  
Blogger Eurodog said...

What?

8:35 pm  
Anonymous Anonymous said...

kinglear - I am so pleased you haven't succumbed to this metrication nonsense. That said, these days 46-36-46 might well be a lady's vital statistics in centi metres given their penchant for dieting. I've never understood why they bother. One only has to look at ITV weather presenters compared to their BBC counterparts to know that not only are slender women less attractive, they are far less bright when it comes to predicting the weather as well.


The Telegraph was going on the other day about something [may have been a garden fence or that Iraqi partition or even the Glastonbury fence] being 6.5 metres.

I was trying to work out whether that was more or less than 20 feet - vital information if one is trying to attempt to vault over it, but without a calculator I couldn't be bothered.

I did used to enjoy those very early pocket calculators, when if you keyed in 69 n! [factorial] it would have to stop and think for about 5 seconds before giving you the answer. [70 n! was too big to display on those early calculators]

Perhaps you could get a guest blog from Mutterings and Meanderings to explain the link between the Fibonacci sequence and the numbers of branches on a tree ? I mean, who tells the tree ? Or do they have a cunningly well hidden calculator?

8:59 pm  
Blogger Welshcakes Limoncello said...

Oh, WW, numbers again! Interesting but I have no brain for them...

10:19 pm  
Anonymous Anonymous said...

have now worked out that the fence would be just over 20 feet tall, so I would probably bang into the top of it and fall back if I was trying to pole vault over it...

9:45 am  
Blogger kinglear said...

Limoncello - do you play the cello??

11:25 am  

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