Re: Quick help needed very much!!!!
- To: mathgroup at smc.vnet.net
- Subject: [mg94014] Re: [mg93992] Quick help needed very much!!!!
- From: Daniel Lichtblau <danl at wolfram.com>
- Date: Tue, 2 Dec 2008 00:40:49 -0500 (EST)
- References: <200811290929.EAA14420@smc.vnet.net> <200811301201.HAA07727@smc.vnet.net> <200812011201.HAA05879@smc.vnet.net>
Artur wrote:
> Dear Mathematica Gurus,
>
> I was run 2 days ago procedure
> aa = {}; bb = {}; Do[
> If[(Sqrt[n! + 1] /. Sqrt[_] -> 1) > 1, Print[n]; AppendTo[aa, n];
> AppendTo[bb, Sqrt[n! + 1] /. Sqrt[_] -> 1]], {n, 1, 10000000}]; aa
>
> Who know how interrupt these with possibility received information about
> value last n checked or received recent value n without interrupting.
>
> If you know answer on my question send copy email answer also on my
> private email, please!
>
> Best wishes
> Artur
You might print n every so often, say when it is a multiple of 100. This
will give you a close bound on where it is upon interruption. Or you
could replace Do with a For loop, and increase your index, n, in each
step. If you interrupt, this index is not a scoped variable (the way it
is in Do) and so you can simply check it's value.
I will point out that if the purpose of your code is to find ALL
n<=10000000 where n!+1 contains a square, there is no reason to believe
it will work correctly. This is because there are numbers containing
squares, for which Sqrt will not pull out those squares. Here is a
fairly small example.
Sqrt[Prime[11111]^2*Prime[22222]]
If I recall correctly, all such examples will have squares that involve
primes larger than Mathematica would use for trial division.
Daniel Lichtblau
Wolfram Research
- References:
- Quick help needed very much!!!!
- From: Artur <grafix@csl.pl>
- Quick help needed very much!!!!