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drummers-lowrise
1) Message boards : Sophie Germain Prime Search : First prime (the 2nd) (Message 140588)
Posted 3 hours ago by Profile JeppeSNProject donor
No need to keep fingers crossed. The prime shows up on your account (when I click your name here in the forum) already, so it does not have any "companion".

The fact that it has no twin was established by your own work, which is why this task took longer than ordinary tasks in this project.

The fact that it is not Sophie Germain (or safe, although the current sieve does not give a good chance for safe primes) was established by the server already.

Congratulations with your prime.

/JeppeSN
2) Message boards : Cullen/Woodall prime search : Woodall ahead Cullen (Message 140586)
Posted 4 hours ago by Profile JeppeSNProject donor
Maybe not a stupid question.

There appear to be more Woodall candidates than Cullen. For example between 17M and 18M, there are 27'992 Woodall candidates, but only 20'304 Cullen.

So there is more work in advancing Woodall.

This corresponds to the fact that there are more Woodalls known than Cullens. (More candidates after relevant sieving means more primes found.)

So the "weight" of Woodall is higher.

/JeppeSN
3) Message boards : Seventeen or Bust : Proposal: A new Sierpiński problem (Message 140585)
Posted 4 hours ago by Profile JeppeSNProject donor
Will these numbers be tested for Fermat divisibility?


Since the values of k are fairly high here, I think the chance of finding a Fermat divisor is quite low. I'll start a test on the new k = 68633 prime anyway and see if anything pops up.


I agree, the chances are minuscule. But we might as well test them, since it is only twelve numbers. /JeppeSN
4) Message boards : Seventeen or Bust : Proposal: A new Sierpiński problem (Message 140564)
Posted 1 day ago by Profile JeppeSNProject donor
And congratulations to beijinghouse!

Do we have proof that there is no k=68633 prime between 68633*2^9 + 1 and 68633*2^2715609 + 1? One could add a user comment on the entry explaining that it is the first Proth prime with this k.

/JeppeSN
5) Message boards : Seventeen or Bust : Proposal: A new Sierpiński problem (Message 140560)
Posted 1 day ago by Profile JeppeSNProject donor
Update with the new prime, 68633*2^2715609 + 1:
k (weight) known non-Proth primes eliminated? --------------------------------------------------------------- 22249 (0.3253) 22249*2^2 + 1 Yes, 22249*2^408602 + 1 23873 (0.3425) 23873*2^5 + 1 Yes, 23873*2^136733 + 1 23971 (0.1180) 23971*2^8 + 1 28831 (0.2716) 28831*2^4 + 1 Yes, 28831*2^204580 + 1 35461 (0.2162) 35461*2^4 + 1 Yes, 35461*2^129820 + 1 39527 (0.1596) 39527*2^15 + 1 Yes, 39527*2^143055 + 1 44243 (0.2793) 44243*2^9 + 1 Yes, 44243*2^440969 + 1 45323 (0.3053) 45323*2^1 + 1 50777 (0.1900) 50777*2^11 + 1 50873 (0.4702) 50873*2^1 + 1 54953 (0.2429) 54953*2^9 + 1 Yes, 54953*2^622065 + 1 57377 (0.1988) 57377*2^7 + 1 Yes, 57377*2^447439 + 1 68221 (0.3995) 68221*2^16 + 1 Yes, 68221*2^200944 + 1 68633 (0.3066) 68633*2^9 + 1 Yes, 68633*2^2715609 + 1 71657 (0.3850) 71657*2^15 + 1 Yes, 71657*2^1146175 + 1 76877 (0.0929) 76877*2^11 + 1 77297 (0.3050) 77297*2^3 + 1 Yes, 77297*2^118499 + 1

/JeppeSN
6) Message boards : Fermat Divisor Search : Fermat Divisor Search (Message 140544)
Posted 1 day ago by Profile JeppeSNProject donor
Even values of n would have been captured by the 321 search, right? That was my assumption for why thy were not being included.


No. A number of the form 9*2^{2*u} + 1 cannot be written as 3*2^n + 1. /JeppeSN
7) Message boards : Number crunching : New T5k Stats (Message 140541)
Posted 1 day ago by Profile JeppeSNProject donor
You write id=120819 "Was 5000 on 2020-01-xx". If you look at the page, it says Removed: 2/10/2020 04:14:26 CDT. That is American notation for 2020-02-10. /JeppeSN
8) Message boards : General discussion : Proposed new formula (Message 140540)
Posted 1 day ago by Profile JeppeSNProject donor
So it turns out the formula is not new. Ravi mentioned OEIS A051783 already. If you could find any new members, you could contribute to that sequence.

But there is also PRP Top. See PRP Top search for 3^n+2. If you found any new ones, you would submit them there.

Since you are not going to be able to prove these numbers prime, they are not going to be admitted into the Prime Pages lists.

/JeppeSN
9) Message boards : Fermat Divisor Search : Fermat Divisor Search (Message 140539)
Posted 2 days ago by Profile JeppeSNProject donor
On Keller's page Riesel's List (List of primes k*2^n + 1 for k < 300), under k=9, he says the search limit is 5'900'000 (and in general he has a news flash that PrimeGrid reached 5'958'000).

But for k=9, is it not a problem that we did only odd n here in PPS-DIV? Because Keller lists all exponents, both even and odd.

Is it not possible that there are undiscovered even n with 4'000'000 ≤ n ≤ 5'900'000 such that 9*2^n + 1 is prime?

(When n is even, 9*2^n + 1 = (3*2^{n/2})^2 +1 is a generalized Fermat, by the way.)

/JeppeSN
10) Message boards : Seventeen or Bust : Proposal: A new Sierpiński problem (Message 140435)
Posted 10 days ago by Profile JeppeSNProject donor
8 days, leading edge 3505321, network traffic 146 GB. No new primes.


Already in the megaprime domain. You guys are fast. /JeppeSN


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