RE: factor
- To: mathgroup@smc.vnet.net
- Subject: [mg12550] RE: [mg12476] factor
- From: Ersek_Ted%PAX1A@mr.nawcad.navy.mil
- Date: Sat, 23 May 1998 18:11:12 -0400
William Mopppett wrote:
|
|Can anyone give me a factor of (10^71 - 1)/9 Mathematica 3.0 says it is
|not prime email
|wmoppet@nsw.bigpond.net.au
|
|
The attempt below is probably the most effective way to do this. My 90
Mhz Pentium worked on it for 14 hours and still didn't find a factor.
The documentation makes it clear you will may not get an answer in a
short amount of time. It also says it is designed to find factors up
to about 18 digits in 3 hours on a "workstation" (what ever that is).
Well it seems all the prime factors of this number have 18 to 35 digits,
and it has two, three, or four prime factors. The number of potential
prime factors to consider is roughly,
( 10^35/Log[10^35] - 10^18/Log[10^18] ) = ( 1.2 * 10^33 ) !!
In[1]:=
<<NumberTheory`FactorIntegerECM`
In[2]:=
FactorIntegerECM[(10^71 - 1)/9 ]
(* still waiting *)
___________________________________
Perhaps you can do better by specifying a value for one or more of the
options.
In[3]:=
Options[FactorIntegerECM]
Out[3]=
{FactorSize -> Automatic,
CurveNumber -> Automatic,
CurveCountLimit -> 10000}
__________________________________
Ted Ersek