[seqfan] Re: Purely algorithmic number sequence identification

[Charles Greathouse]

There are about 100,000 sequences with %F lines and about 150,000 without.
It's probably worthwhile to run it on all the sequences in
oeis.org/stripped.gz.

I think adding the Sequencer to the Superseeker would be great -- at least
through depth 5, which takes a second or two, and possibly to depth 6
depending on our free processor time (in my experiments this takes a few
minutes). I imagine the easiest way would be to run it as a black box,
dumping the result to a temp file?

Yangchen Pan and Max Alekseyev were working on a project looking for
relations between OEIS sequences, they may also have useful information.

Charles Greathouse
Analyst/Programmer
Case Western Reserve University

On Tue, Feb 24, 2015 at 3:37 PM, Philipp Emanuel Weidmann <
pew at worldwidemann.com> wrote:

> Sounds good, how would that work? Sequencer already has a public API
> (documented at https://github.com/p-e-w/sequencer#api) so integration
> should be easy as long as Superseeker has a way to interface with a JVM
> library.
>
> As for A122536, nothing so far I'm afraid. I really would like to run a
> mass search on sequences without formulas though. Do you perhaps know of
> a way to find just those on OEIS? Soon the batch of performance
> improvements I'm currently working on will be finished, and then
> Sequencer should be able to search all depth 6 formulas for more than
> 1000 Sequences per day. Also, a batch mode could be implemented, which
> would allow the program to process a large number of sequences at once,
> dramatically improving performance for this use case. Indeed, all of
> OEIS could be checked this way in about a week probably – which would
> also be interesting for sequences that already *have* formulas, as some
> of them may possess interesting alternative forms, or be incorrect.
>
> Best regards
> Philipp
>
>
>
>
>
> On Tue, 2015-02-24 at 08:17 -0500, Neil Sloane wrote:
> > What do you think of adding your program to Superseeker?  It sounds like
> > this would definitely be worth doing.
> >
> > By the way, can you do anything with A122536?  We have 200 terms, but no
> > formula or recurrence!
> >
> > Best regards
> > Neil
> >
> > Neil J. A. Sloane, President, OEIS Foundation.
> > 11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
> > Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
> > Phone: 732 828 6098; home page: http://NeilSloane.com
> > Email: njasloane at gmail.com
> >
> >
> > On Mon, Feb 23, 2015 at 1:21 PM, Philipp Emanuel Weidmann <
> > pew at worldwidemann.com> wrote:
> >
> > > Well, it turns out the first eight elements of A000001 satisfy the,
> umm,
> > > "slightly exotic" recurrence relation
> > >
> > >   a(1) = 1
> > >   a(2) = 1
> > >   a(n) = Floor(a(n-2)*(2-Sin(2^n)))   for n >= 3
> > >
> > > ;)
> > >
> > > In earnest, while I doubt that brute forcing formulas will bring any
> > > insight into sequences that have baffled mathematicians for centuries
> > > with their irregularity, what might indeed be interesting is to run the
> > > system not on one sequence, but on tens of thousands, all of which have
> > > no closed-form expression associated with them (is there a way to query
> > > those on OEIS?). In a matter of days, Sequencer would likely return a
> > > hundred or so closed forms, some of which may prove correct, which
> could
> > > then be investigated rigorously.
> > >
> > > For such a search, I should probably also add a lot more combinatorial
> > > and number theoretic primitives to the formula generator – whenever I
> > > randomly browse around OEIS, most of the sequences seem to be counting
> > > problems of some kind.
> > >
> > > Best regards
> > > Philipp
> > >
> > >
> > >
> > >
> > > On Mon, 2015-02-23 at 11:02 -0500, W. Edwin Clark wrote:
> > > > On Mon, Feb 23, 2015 at 5:42 AM, Olivier Gerard <
> > > olivier.gerard at gmail.com>
> > > > wrote:
> > > >
> > > > >
> > > > > It would be nice to test it on "hard" sequences and other sequences
> > > without
> > > > > formula.
> > > > >
> > > > >
> > > > >
> > > > For example:  http://oeis.org/A000001, the number of groups of
> order n
> > > :-)
> > > >
> > > > Or perhaps easier:  http://oeis.org/A000688, the number of abelian
> > > groups
> > > > of order n.
> > > >
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