Mersenne Prime Number
06-19-2017, 11:27 AM (This post was last modified: 06-19-2017 11:29 AM by Marcel.)
Post: #1
 Marcel Member Posts: 182 Joined: Mar 2014
Mersenne Prime Number
Hi!
In 1903, Frank Nelson Cole factorise this number:
147 573 952 589 676 412 927 = 193 707 721 x 761 838 257 287

On the Prime, divis() and factor() give no factorisation;
On Ti-Nspire, factor() give a good response.

I know the Prime can do it.

My question:

If the two functions of the Prime is limit in size of the number in ( ), why just say it because the response is not the good one.

Marcel
06-19-2017, 11:42 AM
Post: #2
 Didier Lachieze Senior Member Posts: 1,641 Joined: Dec 2013
RE: Mersenne Prime Number
ifactor(147573952589676412927) returns the right answer

divis & factor are for polynomials, not integers.
06-19-2017, 11:52 AM
Post: #3
 Marcel Member Posts: 182 Joined: Mar 2014
RE: Mersenne Prime Number
Hi Didier!

Thank you..

Marcel
06-19-2017, 05:04 PM
Post: #4
 Gerson W. Barbosa Senior Member Posts: 1,603 Joined: Dec 2013
RE: Mersenne Prime Number
The emulated 50g in Debug4x does it in 9 seconds, Intel E4700 @ 2.60 GHz:

'193707721*761838257287'

The physical HP 50g quits after a while. Hats off to Mr. Cole, who used only pencil and paper!
06-19-2017, 11:04 PM
Post: #5
 Marcel Member Posts: 182 Joined: Mar 2014
RE: Mersenne Prime Number
Hi Gerson,
It took him three years of Sunday time to do this factorization!
Wow!
Marcel
06-20-2017, 12:07 AM
Post: #6
 webmasterpdx Senior Member Posts: 541 Joined: Sep 2015
RE: Mersenne Prime Number
The hp prime does it instantaneously. I've been able to work with numbers with over 2500 digits on the prime. Note that it is annoying that you have to be in cas or home mode depending on the function. I wish that barrier didn't exist.
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