* Robin Houston ([EMAIL PROTECTED]) wrote:
i was actually being a little bit serious, albeit i used a bit of
poetic license, with the horse riding analogy.
however 1 does expose the artificial nature of primes
>
> There's no reason you can't say that 1 is prime if you like though.
> (What do you think about -1?)
i tend to think that has more to do with what are the factorisations
of negative numbers, sure -1 can spill into f. of positive primes, but
thats forced, so lets look at -ive factorisations
-20 = -2 * -2 * -5
-40 = -2 * -2 * -2 * -5 * -1
the -1 makes a difference here
my opinion about this ....
i don't have a feeling for it, i can't feel it like i can
+ive prime number factorisations
maybe 1 is prime, maybe its not ... but it is part of the sequence,
if only like a false start in a car
anyway i've always liked prime factorials more, i.e. numbers that
are the product of the set of primes up to that number (the number
being a prime) e.g.
p! = prime factorial
3 p! = 3 * 2 * 1 = 6
13 p! = 13 * 11 * 7 * 5 * 3 * 2 * 1 = (this is left to
the reader)
now if i recall correctly, and this is unlikely ....
n p! + 1 is a prime
yet with it we leave primes behind, for example above 3 p! + 1 = 7
which skips 5
why is 5 left out? of course it seems obvious that the product
grows so large that it leaves out primes - but it does seem unclean
- but thats the nature of primes
Anyway, excuse the ramblings of an amateur, the next thing you'll
know i'll be changing the[1] words ``Adolf Hitler'' into numbers
and finding ``london.pm meetings held on the day after the first
wednesday of the month'' in them,
goodnight all, and a very good weekend
Greg
[1] plays ``get out of godwin law free'' card
--
Greg McCarroll http://www.mccarroll.uklinux.net
