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Search: Posts Made By: JeppeSN
Forum: Prime Gap Searches 2020-07-09, 07:49
Replies: 51
Views: 6,176
Posted By JeppeSN
True. You can still see the historic versions,...

True. You can still see the historic versions, for example:
A326747 revision #56 (https://oeis.org/history/view?seq=A326747&v=56)
A326829 revision #34...
Forum: Aliquot Sequences 2020-07-08, 09:41
Replies: 15
Views: 253
Posted By JeppeSN
You must first find the full factorization of A,...

You must first find the full factorization of A, and then use the formulas here: Wikipedia: divisor function (https://en.wikipedia.org/wiki/Divisor_function) /JeppeSN
Forum: Aliquot Sequences 2020-07-08, 09:30
Replies: 15
Views: 253
Posted By JeppeSN
Do you mean when the full factorization of the...

Do you mean when the full factorization of the argument is known? /JeppeSN
Forum: Conjectures 'R Us 2020-07-07, 17:55
Replies: 17
Views: 517
Posted By JeppeSN
What are the size of the 32 k values? What k do...

What are the size of the 32 k values? What k do you consider; the odd multiples of 3?

PrimeGrid has used TwinGen (it seems (https://primes.utm.edu/primes/page.php?id=121330)) to sieve for a fixed...
Forum: Operazione Doppi Mersennes 2020-07-06, 20:31
Replies: 10
Views: 535
Posted By JeppeSN
Nice factor! The New Mersenne conjecture is...

Nice factor!

The New Mersenne conjecture is rather silly, but it holds for small numbers, and it is maybe unlikely that large numbers will satisfy just two of the three criteria. It would be fun...
Forum: Conjectures 'R Us 2020-06-30, 23:12
Replies: 5
Views: 271
Posted By JeppeSN
Smile Not sure about the test limit. The BOINC server...

Not sure about the test limit. The BOINC server is at http://boincvm.proxyma.ru:30080/test4vm/server_status.php, the subproject has the name "LLR2 testing", but I do not think the search limit it...
Forum: Conjectures 'R Us 2020-06-30, 21:06
Replies: 5
Views: 271
Posted By JeppeSN
Red face PrimeGrid work on 90646*2^n + 1 and 101746*2^n + 1

In the context of the PrimeGrid forum, the idea to find additional primes in the series 45323*2^n + 1 and
50873*2^n + 1, along with others, came up. They both produce "trivial" primes for n=1.
...
Forum: Proth Prime Search 2020-06-20, 07:55
Replies: 5
Views: 408
Posted By JeppeSN
If you consider the numbers 2^(4k+2) + 1, there...

If you consider the numbers 2^(4k+2) + 1, there are two kinds of algebraic factorizations for them. One is because 4k+2 = 2(2k+1), so the exponent has an odd divisor, therefore:

2^(4k+2) + 1 =...
Forum: Proth Prime Search 2020-06-15, 17:42
Replies: 5
Views: 408
Posted By JeppeSN
Thumbs up That sounds correct. In fact it seems the...

That sounds correct. In fact it seems the Gaussian Mersenne norms includes a bit more candidates, namely 2^{2k+1} ± 2^{k+1} + 1 where the sign of the middle term is picked such that the candidate is...
Forum: Math 2020-06-15, 15:26
Replies: 15
Views: 886
Posted By JeppeSN
This may seem silly, but I ran a test with PFGW...

This may seem silly, but I ran a test with PFGW (slow, one CPU thread) on the remaining number. It took several weeks. Here is the result (PFGW does a 3-PRP test by default):


PFGW Version...
Forum: Math 2020-06-10, 13:38
Replies: 12
Views: 392
Posted By JeppeSN
Thumbs up According to...

According to https://mathshistory.st-andrews.ac.uk/HistTopics/Perfect_numbers/, Ismail ibn Ibrahim ibn Fallus (1194-1239) knew the first seven perfect numbers many years before Pietro Cataldi...
Forum: Math 2020-05-17, 21:07
Replies: 15
Views: 886
Posted By JeppeSN
Yes, I wonder if there is any explanation why the...

Yes, I wonder if there is any explanation why the four of them are prime squares. Apparently not. I did check that 2^74207283 - 7 is not a square, ha ha.

Edit: It has been proved...
Forum: Math 2020-05-17, 20:59
Replies: 15
Views: 886
Posted By JeppeSN
Updated with the latest factor from kruoli. ...

Updated with the latest factor from kruoli.

The only pending is 2^74207282 - 3. The same one that causes trouble with right perfect primes...
Forum: Math 2020-05-17, 18:02
Replies: 15
Views: 886
Posted By JeppeSN
Thumbs up Impressive. Can they be guaranteed to be minimal?...

Impressive. Can they be guaranteed to be minimal?

Only one composite without known factor, and one for which it is not known if it is prime or not. Updating:

p: factor of 2^{p+1} - 3...
Forum: Math 2020-05-17, 10:26
Replies: 15
Views: 886
Posted By JeppeSN
Found a factor of one of them: p: ...

Found a factor of one of them:

p: factor of 2^{p+1} - 3
----------------------------------
2: prime
3: prime
5: prime
7: 11
13: prime
...
Forum: Other Mathematical Topics 2020-05-17, 09:09
Replies: 2
Views: 3,788
Posted By JeppeSN
Arrow In most cases, just correct the wrong data, and...

In most cases, just correct the wrong data, and write in the Extensions section what you did. E.g. write "Wrong entries a(10)-a(20) corrected and additional entries added by" and your name will be...
Forum: Math 2020-05-17, 07:39
Replies: 15
Views: 886
Posted By JeppeSN
Cool Mersenne prime in a Cunningham chain

Often when a Mersenne prime M = 2^p - 1 is found, we check also the numbers M - 2 (twin), (M + 2)/3 (Wagstaff) and M*(M + 1)/2 + 1 (right perfect) to make sure M does not have a "companion" prime.
...
Forum: Software 2020-04-18, 12:20
Replies: 429
Views: 25,697
Posted By JeppeSN
Question Silly question: Which is the preferred place to...

Silly question: Which is the preferred place to download from if I only care about the Windows (x64) binaries, not the source?

On https://www.mersenneforum.org/rogue/mtsieve.html there is a file...
Forum: Riesel Prime Search 2020-04-01, 08:53
Replies: 208
Views: 23,000
Posted By JeppeSN
Arrow There is already a newer and bigger one,...

There is already a newer and bigger one, 9*2^13334487 + 1 (https://primes.utm.edu/primes/page.php?id=130806). He has found 9 huge Proth primes with k in { 9, 11, 13 } in the month of March.

Ryan...
Forum: Sierpinski/Riesel Base 5 2020-03-19, 19:53
Replies: 20
Views: 15,032
Posted By JeppeSN
Fourth one, 207494*5^3017502 - 1. ...

Fourth one, 207494*5^3017502 - 1.

https://primes.utm.edu/primes/page.php?id=130783

/JeppeSN
Forum: Riesel Prime Search 2020-03-16, 17:13
Replies: 208
Views: 23,000
Posted By JeppeSN
Question What ranges was Propper searching, and did he...

What ranges was Propper searching, and did he keep the residues of all the composite candidates he must have covered? This information could be useful to PrimeGrid which is planning to search and...
Forum: Sierpinski/Riesel Base 5 2020-03-14, 10:25
Replies: 20
Views: 15,032
Posted By JeppeSN
Thumbs up And the third one of this month: 238694*5^2979422...

And the third one of this month: 238694*5^2979422 - 1

https://primes.utm.edu/primes/page.php?id=130771

/JeppeSN
Forum: Math 2020-02-07, 16:26
Replies: 36
Views: 4,847
Posted By JeppeSN
forprime(p=2,2^(67/2),(2^67-1)%p==0&&return(p)) ...

forprime(p=2,2^(67/2),(2^67-1)%p==0&&return(p))

(PARI/GP) That is the worst method I can imagine. It tries every prime (ignoring the fact that Mersenne divisors have a special form), it even...
Forum: Computer Science & Computational Number Theory 2020-01-25, 19:01
Replies: 79
Views: 10,640
Posted By JeppeSN
Does this simply say that F30 is composite, or...

Does this simply say that F30 is composite, or does it help to determine whether the cofactor F30 / ((149041*2^32 + 1)*(127589*2^33 + 1)) is composite (Suyama...
Forum: FermatSearch 2020-01-25, 18:03
Replies: 302
Views: 36,678
Posted By JeppeSN
Lightbulb Yes, your number 3*2^5523861 + 1 is composite,...

Yes, your number 3*2^5523861 + 1 is composite, because PrimeGrid has established the primality status of all numbers 3*2^n ± 1 for n up to over 15.5 million, see their page stats_321_llr...
Showing results 1 to 25 of 120

 
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