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Old 2009-03-20, 07:25   #1
schickel's Avatar
"Frank <^>"
Dec 2004
CDP Janesville

212210 Posts
Default Aliquot ranges and status

As of August 2011, all sequences with a starting number below 1000000 have been calculated to a minimum height of 110 digits (some may have dropped back below that size due to recent downdriver activity), and there are 9253 open sequences in that range.

We are, I believe, the largest project right now that is actively pursuing sequences throughout the entire range. Any open ended sequence is available for reservation, with the following possible exceptions:

The Lehmer Five, 276, 552, 564, 660, & 966, along with 1074, 1134, 19560 & 204828 are currently maintained by Paul Zimmermann. Please co-ordinate any work with him.

The 74 sequences from 1200-10000, with the exception of 4788, are maintained by Christophe Clavier and associates. Email Christophe Clavier to reserve these.

4788 is currently reserved as a team project by the members of Mersenneforum. Its primary interest is due to work originally done by Wieb Bosma. His work showed a merge occuring after an extensive run. Further investigation by Clifford Stern showed that it actually merges with 4788 rather than 16100. Since the merge occurs after 6400+ lines, the combined sequence pair 314718/4788 is the longest open sequence at 9000+ lines. Fortunately, stability was achieved at line 2470 and 171 digits with the loss of the '3' factor, eventually followed by a short downdriver run. Stability has now been reached again at 166 digits. Check the 4788 thread for the latest info.

Sequences in the range 10116-99840 are of particular interest to Clifford Stern. This range has been completed to a minimum of 110 digits by the forum, with selected sequences being pursued higher by Clifford. If you wish to work in this range, check with Clifford, he may have completed work that has not been uploaded to the Factoring Database yet. Most sequences that he is working will be called out in the reservation thread here.

1000000-4000000 has been completed up to 71 digits by axn. Currently there is no active project working above 1000000.

Everything else is open for pursuit. Check the reservation thread for current reservations before embarking on any large-scale effort. Links to sites with more in-depth information are available here.

Advice and help on getting started with Aliquot Sequences are available here, just post any questions or problems you might have.

Advice and help on getting started with large-scale factoring efforts are available over in the Factoring Forum.

Last fiddled with by 10metreh on 2012-08-08 at 18:47 Reason: PaulZ is now working 19560 as well
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