Mersenne Semiprimes

[ATH]

Originally Posted by R.D. Silverman

Is there some point to all this?

I saw this problem Mr. P-1 asked about and thought it sounded interesting. I had fun making my little program and optimizing it, and at the same time I also learned how to use mfaktc on composite exponents. It also looked like I was alone working on it, so it gave a sense of "discovery" because no one else had ever checked which of these M(p^2) might be semi prime, compared to just being 1 among many like in GIMPS and many other projects.

I'm continuing factoring those 15 remaining numbers a bit more.

[R.D. Silverman]

Originally Posted by ATH

so it gave a sense of "discovery" because no one else had ever checked which of these M(p^2) might be semi prime.

You might want to consider the reason why noone else had done it before...

[bsquared]

Originally Posted by R.D. Silverman

You might want to consider the reason why noone else had done it before...

To paraphrase one of my favorite physicists: "Why should he care what anyone else thinks?"

He derives enjoyment from what he's doing, he's not hurting anyone, and in fact is learning something from what he's doing. I don't understand why we're even having this conversation.

[R.D. Silverman]

Originally Posted by bsquared

To paraphrase one of my favorite physicists: "Why should he care what anyone else thinks?"

He derives enjoyment from what he's doing, he's not hurting anyone, and in fact is learning something from what he's doing. I don't understand why we're even having this conversation.

He doesn't have to care. But if he is going to present ideas in public,
then he can expect feedback from others. One such feedback might
be what I have presented, i.e. "this isn't useful". The OP is, of course,
entitled to ignore said opinion.

Consider the subforum. This is mathematics. I don't see any math.
I do see numerology and mindless computing.

Why is it that noone ever seems to say/ask: "I am new. What would be a
good project to work on?". Instead, people seem to latch onto meaningless
number crunching that really isn't useful. Mental masturbation should be
kept private.

I never suggested that he is not entitled to present his "ideas". But just as
he is free to post numerology, I am free to say "This isn't useful; try something else"

Allow me to quote again: "The purpose of computing is insight, not numbers".

[CRGreathouse]

Originally Posted by R.D. Silverman

Allow me to quote again: "The purpose of computing is insight, not numbers".

Absolutely.

Originally Posted by R.D. Silverman

Instead, people seem to latch onto meaningless
number crunching that really isn't useful. Mental masturbation should be
kept private.

Unless it's the Cunningham project, right?

[R.D. Silverman]

Originally Posted by CRGreathouse

Absolutely.



Unless it's the Cunningham project, right?

As I have said before, I agree with Oliver Atkin.
The Cunningham project, by itself, is just a stamp collection.

The purpose of the Cunningham project is not to factor certain numbers, but
rather to provide a collection of related numbers (they do have some
historical background) that serve as a useful benchmark for pushing the
state of the art in factoring algorithms. And the factorizations are (rarely, I
would agree) sometimes useful.

Factoring Cunningham numbers does not solve any open mathematical
problems. OTOH, There are projects that are working on open
problems. e.g. 17 or Bust, the Euler project etc.

I'd like to complete the first edition of the Cunningham book (all that
remains is the current base 2 tables) because I promised Dick Lehmer
that I would push toward finishing them. This is a realizable
goal. The topic that started this thread is not a realizable goal.

[CRGreathouse]

Originally Posted by R.D. Silverman

As I have said before, I agree with Oliver Atkin.
The Cunningham project, by itself, is just a stamp collection.

The purpose of the Cunningham project is not to factor certain numbers, but
rather to provide a collection of related numbers (they do have some
historical background) that serve as a useful benchmark for pushing the
state of the art in factoring algorithms. And the factorizations are (rarely, I
would agree) sometimes useful.

I feel the same way.

[Mr. P-1]

Originally Posted by R.D. Silverman

Consider the subforum. This is mathematics. I don't see any math. I do see numerology and mindless computing.

Why is it that noone ever seems to say/ask: "I am new. What would be a
good project to work on?". Instead, people seem to latch onto meaningless
number crunching that really isn't useful. Mental masturbation should be
kept private.

Most people round these parts seem to think that the search for Mersenne primes is a good project to work on. That too is numerology and mindless computing for the vast majority of participants.

You're entitled to your view that it should be kept private, of course. Expressing that view in the Mersenne mental masturbators' forum would appear to be..., well, pointless.

Originally Posted by R.D. Silverman

As I have said before, I agree with Oliver Atkin.
The Cunningham project, by itself, is just a stamp collection.

The purpose of the Cunningham project is not to factor certain numbers, but
rather to provide a collection of related numbers (they do have some
historical background) that serve as a useful benchmark for pushing the
state of the art in factoring algorithms.

I am at a loss to understand how soliciting contributions of mindless computation from random passers by will in any way contribute to pushing the state of the art in factoring algorithms.

On the other hand, I do see how it would help you complete your stamp collection.

I'd like to complete the first edition of the Cunningham book (all that
remains is the current base 2 tables) because I promised Dick Lehmer
that I would push toward finishing them.

That you made a promise to another person to mentally masturbate on his behalf is probably something to be kept private.

This is a realizable
goal. The topic that started this thread is not a realizable goal.

Completing the first edition of the Cunningham book was not foreseeably a realizable goal in 1925 when that book was published. Who knows what will be realizable in eighty-five years from now?

[R.D. Silverman]

Originally Posted by Mr. P-1

I am at a loss to understand how soliciting contributions of mindless computation from random passers by will in any way contribute to pushing the state of the art in factoring algorithms.

That is how the community learns to select the parameters for larger
numbers. It is how we learn to tune our code. It is how we learn
whether algorithms match theoretical predictions for their
performance. By actually DOING.

Individuals do not have enough CPUs to do the work, so outside
help is solicited.

[Jens K Andersen]

Getting back to the pointless computations instead of discussing their pointlessness, at http://donovanjohnson.com/mersenne.html I think I found the 5 largest known probable Mersenne semiprimes :
M(684127) = 23765203727 * prp205933
M(406583) = 813167 * prp122388
M(271549) = 238749682487 * prp81734
M(271211) = 613961495159 * prp81631
M(221509) = 292391881 * prp66673

The largest proven Mersenne semiprime at http://primes.utm.edu/top20/page.php?id=49 is:
M(17029) = 418879343 * p5118

[cheesehead]

Originally Posted by R.D. Silverman

Is there some point to all this?

The learning process you went through (particularly compact because of your natural ability and circumstances) before the Internet is being played out on the Web in public now, which was never before possible. Had it been, one would have seen a similar mix of folks' learning levels exhibited on that earlier Web then, I'm fairly sure.