Mersenne Prime Number

06192017, 11:27 AM
(This post was last modified: 06192017 11:29 AM by Marcel.)
Post: #1




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 TiNspire, 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 

06192017, 11:42 AM
Post: #2




RE: Mersenne Prime Number
ifactor(147573952589676412927) returns the right answer
divis & factor are for polynomials, not integers. 

06192017, 11:52 AM
Post: #3




RE: Mersenne Prime Number
Hi Didier!
Thank you.. Marcel 

06192017, 05:04 PM
Post: #4




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! 

06192017, 11:04 PM
Post: #5




RE: Mersenne Prime Number
Hi Gerson,
It took him three years of Sunday time to do this factorization! Wow! Marcel 

06202017, 12:07 AM
Post: #6




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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