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Search: Posts Made By: 10metreh
Forum: YAFU 2020-02-15, 14:55
Replies: 475
Views: 40,823
Posted By 10metreh
Don't think this one's turned up before: ...

Don't think this one's turned up before:

02/15/20 06:53:28 v1.35-beta @ BLACKBOX2,
02/15/20 06:53:28 v1.35-beta @ BLACKBOX2, ****************************
02/15/20 06:53:28 v1.35-beta @...
Forum: Miscellaneous Math 2019-10-23, 14:29
Replies: 50
Views: 2,544
Posted By 10metreh
Consider the equation 3d+4e = 6d+2e. This is...

Consider the equation 3d+4e = 6d+2e.
This is true for the specific values d = 2 and e = 3, for example. This does not allow us to conclude that 3 = 6 and 4 = 2.

(Also from what I can tell the...
Forum: Miscellaneous Math 2019-04-06, 19:32
Replies: 15
Views: 749
Posted By 10metreh
There are lots of very smart people on...

There are lots of very smart people on stackexchange but they don't like being given long messy expressions like yours, with no explanation of how they were derived, and asked to simplify them. Most...
Forum: Miscellaneous Math 2019-04-06, 16:57
Replies: 15
Views: 749
Posted By 10metreh
The expression is equal to 1 for all n (including...

The expression is equal to 1 for all n (including pseudoprimes and composites).

First we deal with the finite sum. It turns out it can be written in a much simpler form.

\sum _{p=1}^{2k}...
Forum: Miscellaneous Math 2019-02-04, 23:40
Replies: 40
Views: 1,729
Posted By 10metreh
Bringing back an argument I've used before. ...

Bringing back an argument I've used before.

Proof that there are infinitely many primes of the form n2-1:

Suppose there are finitely many primes of this form. Then there must be a prime that...
Forum: Conjectures 'R Us 2019-01-07, 10:59
Replies: 127
Views: 18,404
Posted By 10metreh
It would be if it was actually smaller than...

It would be if it was actually smaller than 1429458644604553 and had a covering set (I haven't found a prime yet, but what is the factor for n=15?)
Forum: Conjectures 'R Us 2018-12-31, 18:11
Replies: 127
Views: 18,404
Posted By 10metreh
covering.exe has a bug when searching very large...

covering.exe has a bug when searching very large k. There is a version bigcovering.exe which fixes this bug - it's available from the same site as covering.exe.

The likely CK for this base is...
Forum: And now for something completely different 2018-04-13, 11:09
Replies: 11
Views: 2,916
Posted By 10metreh
But this doesn't affect the finiteness or...

But this doesn't affect the finiteness or otherwise of the sequence, as Cunningham chains are finite. Also, as the terms get larger, the probability of hitting a Cunningham chain
should tend to 0...
Forum: And now for something completely different 2018-04-12, 08:45
Replies: 11
Views: 2,916
Posted By 10metreh
It feels like these sequences ought to be finite....

It feels like these sequences ought to be finite. The only long-term modular restriction I can think of for members of the sequence is that they cannot be 1 mod p for any p other than 2 and the...
Forum: Aliquot Sequences 2018-04-03, 12:25
Replies: 6
Views: 2,525
Posted By 10metreh
It is correct - look carefully at the brackets.

It is correct - look carefully at the brackets.
Forum: Aliquot Sequences 2018-04-03, 00:12
Replies: 6
Views: 2,525
Posted By 10metreh
Yes: oeis.org/A146556 Seems not -...

Yes: oeis.org/A146556



Seems not - actually g(3) = 30, and g(4) = 492. The only OEIS match for these terms is oeis.org/A143414 which is clearly unrelated.
Forum: FactorDB 2018-04-02, 13:23
Replies: 21
Views: 5,385
Posted By 10metreh
The thing is, they do. It appears that you...

The thing is, they do.

It appears that you are computing the aliquot sequence of 2^(p-1)*(2^p-1)*3 for some Mersenne prime 2^p-1. If a has no common factors with 2^(p-1)*(2^p-1), then...
Forum: Miscellaneous Math 2018-03-06, 18:08
Replies: 21
Views: 1,883
Posted By 10metreh
Point 3 tells me that if 104 goes down to 1, then...

Point 3 tells me that if 104 goes down to 1, then so does 13. How does knowing 4, 14, 24, 34, 44 and 54 go down to 1 prove that 104 does?
Forum: Miscellaneous Math 2018-03-03, 14:07
Replies: 53
Views: 2,875
Posted By 10metreh
Yes, I agree you've proved your expression (which...

Yes, I agree you've proved your expression (which you're calling an equation although it doesn't have an equals sign in it) cannot equal 0. But this doesn't imply there are infinitely many twin...
Forum: Miscellaneous Math 2018-03-02, 20:38
Replies: 53
Views: 2,875
Posted By 10metreh
I fully understand this, and I never said you...

I fully understand this, and I never said you believed it. What you're doing is a proof by contradiction, where you assume that something is true (in this case, that there is a prime that "ends all...
Forum: Miscellaneous Math 2018-03-02, 19:55
Replies: 53
Views: 2,875
Posted By 10metreh
Here's a proof that there are infinitely many...

Here's a proof that there are infinitely many primes of the form n2-1:

Suppose there are finitely many primes of the form n2-1.
Then there is some prime p which "ends the possibilities" of...
Forum: Miscellaneous Math 2018-03-02, 19:44
Replies: 21
Views: 1,883
Posted By 10metreh
Am I correct in thinking you're saying that...

Am I correct in thinking you're saying that knowing 4, 14, 24, 34, 44 and 54 go down to 1 proves everything goes down to 1? If so, how does your proof show that 13 goes down to 1?
Forum: Conjectures 'R Us 2018-01-25, 20:02
Replies: 127
Views: 18,404
Posted By 10metreh
Back in 2011 I posted lists of conjectured ks for...

Back in 2011 I posted lists of conjectured ks for bases 1031 to 2048 in this thread. Since then I found smaller ks for a few very difficult bases, so here are some updated lists. I know it's likely...
Forum: gophne 2018-01-07, 09:24
Replies: 272
Views: 16,151
Posted By 10metreh
I don't think you've taken on board what axn...

I don't think you've taken on board what axn meant by this:



The point is that, if n is odd, then gcd(n, n+2N) = gcd(n, N) and so you are just checking if n has any common factors with N. But...
Forum: gophne 2018-01-06, 10:39
Replies: 272
Views: 16,151
Posted By 10metreh
CRGreathouse has answered most of the questions...

CRGreathouse has answered most of the questions so there isn't much more for me to say.



According to the Prime Pages (http://primes.utm.edu/glossary/xpage/Fermat.html), Fermat noticed that 2p...
Forum: gophne 2018-01-05, 23:17
Replies: 272
Views: 16,151
Posted By 10metreh
Gophne, as actual proofs don't seem to have...

Gophne, as actual proofs don't seem to have persuaded you, let's have a look at an example to see that the two tests are the same. I'm going to avoid modular arithmetic as much as possible because it...
Forum: Prime Gap Searches 2018-01-01, 14:11
Replies: 187
Sticky: Prime Gap News
Views: 24,520
Posted By 10metreh
These are not upper bounds on gaps. Zhang proved...

These are not upper bounds on gaps. Zhang proved that there are infinitely many prime gaps smaller than 70,000,000. This does NOT mean that all gaps are smaller than 70,000,000.

In fact...
Forum: gophne 2017-12-31, 23:58
Replies: 29
Views: 3,408
Posted By 10metreh
Here is some Pari code to run your test for...

Here is some Pari code to run your test for numbers n+2 from 1 to 10000, and print the false positives along with a counter:
x=0;for(n=-1,9998,if(isprime(n+2)==0&&(2^n-1)%(n+2)==(n+1)/2,x++;print(x"...
Forum: gophne 2017-12-31, 19:25
Replies: 272
Views: 16,151
Posted By 10metreh
"mod" isn't an operator. You can't just apply it...

"mod" isn't an operator. You can't just apply it to one side of an equation. It isn't the same as the "%" operator in many programming languages, though it is somewhat similar.

When we say that a...
Forum: Miscellaneous Math 2017-12-29, 22:36
Replies: 69
Views: 3,697
Posted By 10metreh
I don't come here very often, but this caught my...

I don't come here very often, but this caught my attention. This is an incredibly bold claim, especially when many of the finest mathematicians of the last two centuries have tried to prove these...
Showing results 1 to 25 of 1000

 
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