Re: Switching to Linux, now what to buy?

From: Enrique Perez-Terron (enrio_at_online.no)
Date: 09/25/05 

Date: Sun, 25 Sep 2005 10:53:43 +0200

On Sun, 25 Sep 2005 05:00:17 +0200, Peter T. Breuer <ptb@oboe.it.uc3m.es>
wrote:

> Enrique Perez-Terron <enrio@online.no> wrote:
>> On Sat, 24 Sep 2005 22:55:39 +0200, Peter T. Breuer
>> <ptb@oboe.it.uc3m.es>
>> wrote:
>
>>> Peter T. Breuer <ptb@oboe.it.uc3m.es> wrote:
>>>> Jean-David Beyer <jdbeyer@exit109.com> wrote:
>>>>> Peter T. Breuer wrote:
>>>>>> Michael Heiming <michael+USENET@www.heiming.de> wrote:
>>>>>>> In comp.os.linux.setup Peter T. Breuer <ptb@oboe.it.uc3m.es>:
>>>>>>>> Jean-David Beyer <jdbeyer@exit109.com> wrote:
>>>>>>>>> Peter T. Breuer wrote (in part):
>>>>>>>>>>
>>>>>>>>>> 1 2 4 6 10 12 ..
>
>> Add one and you get a prime.
>
>> f(n) = "the n'th prime, minus one"
>
> Very good. Correct.
>
> Exactly how did you think of it? That's very hard to produce by
> analytic resolution.

No analytic resolution. After having warmed up the gray matter with
writing the previous post, I asked myself again:

   Don't I know any simple sequence that increases in this somewhat
   irregular fashion?

and something inside there echoed a word from the previous post:
"the sequence of primes".

I looked at the first number, 1, and thought "The first prime is
two, difference: one." Then I realized it instantly.

I had it perhaps no more than 30 seconds after posting.

Do you know the Physics researcher's proof that all odd numbers
are prime? 1 satisfies most definitions of 'prime', 3 is one, and
so is 5. 7 too. looks good. 9... must be a measurement error, lets
get some more samples. 11: good, 13: good. QED.

Actually I concluded from writing the first post that the solution
should involve at most a single choice for a starting value, and
hardly more than two more steps. But, as touched in the post,
the initial set of "primitive" operations was too narrow.

Actually the original idea when I started "analyzing" the problem
in the post was that I felt I was blocking myself from seeing the
obvious, and I have sometimes managed to force myself over that
barrier by looking hard at the search space definition. I started
writing with the conviction I was not going to post it, but since
I did not find out much I thought perhpas it could spark off
something in one of the others. It did, but in myself.

-Enrique

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