Leyland Primes (x^y+y^x primes)

[NorbSchneider]

Another new PRP:
14596^17691+17691^14596, 73670 digits.

[NorbSchneider]

Another new PRP:
2067^25516+25516^2067, 84595 digits.

[pxp]

Originally Posted by NorbSchneider

Another new PRP...

Norbert posts these so that I don't accidentally submit to PRPtop the same number, on the smallish chance that I have come across it before PRPtop lists it. Because Norbert and I use different approaches as to which Leyland numbers to test for primality, there is some overlap that allows this to happen, although I will say that the closest I have come to rediscovering one of his primes is about two weeks. I don't know how close he has come to rediscovering one of mine.

I don't post my individual finds here of course, feeling that it is sufficient to post them to PRPtop and update my indexed list. As I write, there is a captcha timeout error that prevents me from posting my two most recent finds to PRPtop so I will note these with an asterisk in my list, until such a time as the issue is resolved.

[xilman]

A quick check of the XYYXF site shows it has not been updated in almost three years. Anyone know what's happening?

[pxp]

Originally Posted by xilman

A quick check of the XYYXF site shows it has not been updated in almost three years. Anyone know what's happening?

I have stated previously here (page 25) that "Andrey Kulsha has been missing (I'm guessing that he died) since his last update in January 2017."

[rogue]

I wonder. Have you done a google search? Could this be him: https://scholar.google.com/citations...DkAAAAJ&hl=en? It was updated this year.

Maybe he forgot or got bored or no longer has access.

[pxp]

Originally Posted by rogue

I wonder. Have you done a google search? Could this be him: https://scholar.google.com/citations...DkAAAAJ&hl=en? It was updated this year.

Maybe he forgot or got bored or no longer has access.

Good call. I emailed both authors of the paper and Dmitry Sharapa already got back to me:


"Last time I received message from Andrey 1.September 2019, it was related to our paper. After that we did not keep any contact.

I would not be over pessimistic about him without more significant proves for following reasons:
He also took active part in 'chemport.ru' forum and there are no posts from him after 4.August 2019, but system claims that his last visit to that forum was just yesterday.
To my knowledge he married last summer, so he might have some other activities.

Anyway I sent him message in Slack (was our way of communication during work on the project) and if he will answer - I’ll let you know."

[swellman]

Hope Andrey comes back. I tried to keep the faith, monitored Yoyo’s efforts and added any surviving composite cofactors to the end of the queue after an ECM hit. Looks like all XYYXF numbers will be tested to the full t55 level within the next few months.

Also hoping to get a few of the C3XX numbers into the 16e queue. Several have been tested to the t65+ level now.

It would be really nice to have Andrey back!

[/rambling nonsense]

[pxp]

From Andrey:

"I'm still alive but deeply buried into computational chemistry. I still hope that XYYXF project will resurrect sometime :)"

[xilman]

Originally Posted by pxp

From Andrey:

"I'm still alive but deeply buried into computational chemistry. I still hope that XYYXF project will resurrect sometime :)"

Perhaps I should mail him asking how much he knows about driving DIRAC. I'm technically computing the energies and line strengths of the FeH spectrum but haven't worked on it for ~3 years now. Astronomy took over.

[rogue]

Originally Posted by pxp

From Andrey:

"I'm still alive but deeply buried into computational chemistry. I still hope that XYYXF project will resurrect sometime :)"

Maybe he could give you or someone else update access to the website or maybe it could be moved elsewhere. With Russia building its own internet, who knows how long it will be before that site is not accessible to anyone outside of Russia.