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Topic: Largest primeproduct with 2 as factor?
Replies: 19   Last Post: Aug 16, 2007 1:06 PM

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mensanator

Posts: 5,039
Registered: 12/6/04
Re: Largest primeproduct with 2 as factor?
Posted: Aug 15, 2007 6:55 PM
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On Aug 15, 5:42 pm, Randy Poe <poespam-t...@yahoo.com> wrote:
> On Aug 15, 6:36 pm, jonas.thornv...@hotmail.com wrote:
>
>
>
>
>

> > On 16 Aug, 00:18, stephane.fr...@gmail.com wrote:
>
> > > On Aug 15, 3:03 pm, jonas.thornv...@hotmail.com wrote:
>
> > > > On 16 Aug, 00:00, stephane.fr...@gmail.com wrote:
>
> > > > > On Aug 15, 2:53 pm, jonas.thornv...@hotmail.com wrote:
>
> > > > > > I do not know much math, i just wonder if there is a largest
> > > > > > primeproduct with two as one of the factors.
> > > > > > Same i wonder for three.

>
> > > > > > If not..., but if so is it true for any primefactor used in
> > > > > > primeproduct that they will have a range?
> > > > > > Do every factor have a range in primeproducts?

>
> > > > > > A pure guess tell me that the numbers of primeproducts with 2 or 3
> > > > > > used as one of the factor is infinite but i am not sure.

>
> > > > > > JT
>
> > > > > You guess is right. This is because there is infinity prime number
> > > > > then if N is the bigger prime product, you will find A your biggest
> > > > > prime with A = N/2. You can find a prime number A' with A'> A, then N'
> > > > > = A x 2 > N. Same rules with 3 or any prime numbers.

>
> > > > > SF
>
> > > > Could anyone tell me the biggest "known" primeproduct that has two as
> > > > factor?- Hide quoted text -

>
> > > > - Show quoted text -
>
> > > Well dude , you can suppose you got one and then prove that you can a
> > > bigger one .- D?lj citerad text -

>
> > > - Visa citerad text -
>
> > Ok an easy question i do not have any primeproduct algorithm going, so
> > i would be interested in a list of primeproducts less than a million
> > that has two as factor?

>
> > Can not be that many or?
>
> > If not that many would be nice for 10 000 000 and for 100 000 000?
>
> > Well if already a million would have couple of 100 i am not that
> > interested in the bigger numbers.

>
> What do you mean by "primeproduct"? Do you mean any
> number that has 2 as a factor?


Maybe he means a single factor of 2?

So that it would have to be congruent to 2 (mod 4).

>
> For instance, does 2^20 = 1048576 qualify as a "primeproduct"?
>
> If you just mean any number that has two as a factor,
> these are called "even numbers", and any number that
> ends in 0, 2, 4, 6, or 8 is such a number.


2 (mod 4) would be 2, 6, 10, 14, 18, ...

> Thus, here
> is a large even number: 7924720394820394812476
>
> I guarantee that has 2 as a factor.


>>> print digits(7924720394820394812476,2)
1101011011001100110010110100011000001111011111010111110100000010000111100

Two factors of 2.

>
> - Randy





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