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Old 2015-10-30, 22:02   #1
rogue
 
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Default Mathworld, and ReverseSmarandache Primes

I've been in contact with Eric Weinstein (who manages the Mathworld website). He is interested in some of the searches being done by mersenneforum and PrimeGrid. If you are interested in doing something "different", check out these links:

http://mathworld.wolfram.com/Consecu...Sequences.html
http://mathworld.wolfram.com/ConstantPrimes.html
http://mathworld.wolfram.com/IntegerSequencePrimes.html

I've invited Eric to join (or rejoin) mersenneforum. I think that with the brains on this forum we should be able to develop some projects to extends the searches. One in particular is for Smarandache-Wellin primes (see separate thread). I've already modified pfgw to support that form natively and would be willing to modify pfgw for other searches. I am also willing to help write sieving code for some of those searches.

If you are interested in any of those searches, start a new thread to drum up some interest.
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Old 2015-10-30, 22:14   #2
science_man_88
 
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well I look up a lot sometimes and I know that there's quite a few threads related to this like the smarandache primes thread. and a puzzle about the reversing concatenation version of the sequence, pi primes semi relate to the primes in pi thread though that's slightly different.
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Old 2015-10-30, 23:10   #3
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Good luck with PrimeGrid!

When I posted there about the on-going Smarandache prime search, my post was removed as spam and I've been given a lecture by email. Not automatically generated, mind you, no - hand written and, in particular, comparing my posting to "selling shoes".

I cannot believe that someone would be so deluded as to consider PrimeGrid volunteer resources as somehow their subordinates and "protect" that workforce from "leaking" to other potential projects, and zealously censoring their forum from such dangerous postings. They own that workforce, it seems. But that's ok. I've seen the Communist Party and I've seen censorship - nothing new here; I can recognize the same symptoms in people, and I know towards what bright future they will march their masses on. They own them.

NIH. "Not Invented Here". A sadly familiar attitude.
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Old 2015-10-31, 02:23   #4
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Interestingly, after checking PNACP (Crandal, Pomerance, 2005, 2nd ed., p.78 72), I found that it lists SmW(719) (which is SmWp(128)) as the first non-trivial prime, which appears to be correct, while the note on MathWorld's page refers to something else (possibly to the 2001 or 2002 edition):
Quote:
Note that Crandall and Pomerance 2005, p. 72 erroneously list 5441 as a term, whereas actually p719 = 5441 and 2...3...5.7...5441 is.
Maybe reference on the webpage (to the 2nd ed, dated 2005) has been automatically updated, but the text of the parenthesized note refers to earlier editions only.
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Old 2015-11-02, 15:53   #5
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Yes, the comment in question applied to the 1st edition but the reference got updated to the 2nd edition, where it no longer applies. Fixed on http://mathworld.wolfram.com/Smarand...llinPrime.html
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Old 2015-11-02, 16:04   #6
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Default p#-1 and OEIS A057704

It seems https://oeis.org/A057704

2, 3, 5, 6, 13, 24, 66, 68, 167, 287, 310, 352, 564, 590, 620, 849, 1552, 1849

misses recently found large p#-1 primes; cf. e.g. http://primes.utm.edu/top20/page.php?id=5 and http://prpnet.primegrid.com:12008/user_primes.html. Does anyone know the complete list of additional primes to bring it up to date?

I.e., are there any other primes between 1587# - 1 and 843301# - 1?
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Old 2015-11-03, 03:07   #7
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Hi Eric,
Welcome back to the forum!

I had a question about Smr(n) primes: you have found the second PRP in 2010 (n=37765), but how far did you search? Are you still searching?
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Old 2015-11-03, 04:10   #8
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Quote:
Originally Posted by ericw View Post
It seems https://oeis.org/A057704

2, 3, 5, 6, 13, 24, 66, 68, 167, 287, 310, 352, 564, 590, 620, 849, 1552, 1849

misses recently found large p#-1 primes; cf. e.g. http://primes.utm.edu/top20/page.php?id=5 and http://prpnet.primegrid.com:12008/user_primes.html. Does anyone know the complete list of additional primes to bring it up to date?

I.e., are there any other primes between 1587# - 1 and 843301# - 1?
I assume you meant 15877# - 1. I guess PrimeGrid checked all the numbers from 700k on their PRPNet server. Whether any were missed below that is debatable.

Last fiddled with by paulunderwood on 2015-11-03 at 04:13
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Old 2015-11-03, 12:13   #9
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Quote:
Originally Posted by Batalov View Post
Hi Eric,
Welcome back to the forum!?
Thanks.

Quote:
Originally Posted by Batalov View Post
I had a question about Smr(n) primes: you have found the second PRP in 2010 (n=37765), but how far did you search? Are you still searching?
Yes, still searching. As of today the search has reached 47889 47888 ... 3 2 1 without finding any more PRPs.
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Old 2015-11-03, 14:18   #10
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Quote:
Originally Posted by paulunderwood View Post
I assume you meant 15877# - 1.
Indeed. Another question for Paul or anyone else (I am having trouble rejoining primeform on Yahoo groups to ask there.) I see PrimeGrid has been busily finding new Thabit ibn Kurrah primes 3*2^n - 1. I found some references to that search in various places:

https://groups.yahoo.com/neo/groups/...messages/11558
http://primes.utm.edu/bios/page.php?id=950
http://www.primegrid.com
http://boinc.berkeley.edu

However, I did not manage to find a page listing the current status/search limits. Any know if there is one?

Also, may I infer from the above that Paul's 321 search

http://www.mersenneforum.org/321sear...%20search.html

is no longer active? Thanks.
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Old 2015-11-03, 14:52   #11
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Please check this address:

http://www.primegrid.com/server_status_subprojects.php
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