mersenneforum.org

mersenneforum.org (https://www.mersenneforum.org/index.php)
-   Aliquot Sequences (https://www.mersenneforum.org/forumdisplay.php?f=90)
-   -   Sequence terminations and merges (https://www.mersenneforum.org/showthread.php?t=11837)

Andi47 2009-09-11 15:12

[QUOTE=10metreh;189474]I've listed it as a termination - I think it should only be a merge if the sequence that it merges into is open.

But this would cause problems if someone found a merge, countinued working on the merged sequence, and terminated it...

...but luckily we haven't had that happen yet.[/QUOTE]

Then it would only be a "merge" as long as it is not terminated.

10metreh 2009-09-11 15:17

[QUOTE=Andi47;189484]Then it would only be a "merge" as long as it is not terminated.[/QUOTE]

Right, this is getting a bit confusing. If the scenario I mentioned does happen, then I will get REALLY confused. Therefore all we need to do to get me really confused is to [spoiler]get biwema to work on all the sequences mentioned in the last column of the table in the first post. (i.e. 126792, 660, 102936 etc.)[/spoiler] :wink:

Greebley 2009-09-11 17:07

If a sequence can go from open ended to prime, then I think one could go from merge to prime as well.

I think the ultimate find would be a sequence that merges with itself. If so you have found a cycle that is hundreds or thousands long and beat the mere 28 that is the record now.

10metreh 2009-09-11 17:09

[QUOTE=Greebley;189497]I think the ultimate find would be a sequence that merges with itself. If so you have found a cycle that is hundreds or thousands long and beat the mere 28 that is the record now.[/QUOTE]

My bet with myself is that a cycle at least 1000 iterations long will be found by the end of 2012.

(The chances are higher than you might expect - about 1/6 of the numbers below 1000000 do not terminate in a prime, but are either open or merged. So 276 does not just have to drop down to 276 to merge - it could drop to 306, 396 or any other number that merges with it and still a really long cycle would be formed.)

smh 2009-09-14 19:50

I forgot to report this.

914850 terminates

Thanks to kar_bon for notifying mee.

unconnected 2009-09-15 19:29

[URL="http://factordb.com/search.php?se=1&aq=546120&action=last20&fr=&to="]546120[/URL] merges at i=1645 with 334034

Greebley 2009-09-15 23:54

I got another termination after reaching 115 digits at index [URL="http://factorization.ath.cx/search.php?se=1&aq=507924&action=range&fr=678&to=691"]686[/URL] i.e. [URL="http://factorization.ath.cx/search.php?se=1&aq=507924&action=last20"]507924[/URL] terminates with the same number of digits as my first termination.
[URL="http://factorization.ath.cx/aliquot.php?type=1&aq=507924&big=1"]Graph[/URL]

The previous one to reach 115 digits, [URL="http://factorization.ath.cx/search.php?se=1&aq=151752&action=last20"]151752[/URL] was 'third place' for highest sequence that terminates, so this would be 4th largest being 3x smaller.

RobertS 2009-09-16 14:27

[URL="http://factorization.ath.cx/search.php?se=1&aq=546504&action=last20&fr=&to="]546504[/URL] merges with 660 at i2378

RobertS 2009-09-17 18:33

[URL="http://factorization.ath.cx/search.php?se=1&aq=552018&action=last20&fr=&to="]552018[/URL] is Prime!!!

Greebley 2009-09-18 20:43

I noticed a difference between the DB and the summary page while doing a check.

569244 merges, but it doesn't seem to be listed. Perhaps someone forgot to report it? In any case it belongs here and on the summary page as merged.

Edit: Same with 957726, and 974120.

henryzz 2009-09-19 07:34

[quote=Greebley;190255]I noticed a difference between the DB and the summary page while doing a check.

569244 merges, but it doesn't seem to be listed. Perhaps someone forgot to report it? In any case it belongs here and on the summary page as merged.

Edit: Same with 957726, and 974120.[/quote]
none of those sequences have are mentioned anywhere on mersenneforum
if the merges we found by our project then they need claiming


All times are UTC. The time now is 20:35.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.