[seqfan] Re: Purely algorithmic number sequence identification

[apovolot at gmail.com]

Could usage of the prefix
formula: 
be somehow employed to the sequences with no formulas present at all ?

> On Feb 24, 2015, at 6:17 PM, Frank Adams-Watters <franktaw at netscape.net> wrote:
> 
> If you search in the native format for sequences without "%F" lines, you will find the sequences with no formulas present at all. This still leaves a larger number of sequences for which some formula has been added, but not a formula specifically to define the sequence.
> 
> Franklin T. Adams-Watters
> 
> -----Original Message-----
> From: Philipp Emanuel Weidmann <pew at worldwidemann.com>
> To: seqfan <seqfan at list.seqfan.eu>
> Sent: Tue, Feb 24, 2015 5:09 pm
> Subject: [seqfan]  Re: Purely algorithmic number sequence identification
> 
> 
> 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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>> >
>> >
>> >
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>> >
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>> >
>> 
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