[seqfan] Re: Run Superseeker on existing sequence?

Alexander P-sky apovolot at gmail.com
Fri Aug 13 22:47:47 CEST 2010


Just FYI - WolframAlpha gives for the same input

Possible closed form:
a_n = 2 n-1 (for all terms given)
Possible continuation:
1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51,...
Possible generating function:
(script capital g)_n(a_n)(z) = (z+1)/(z-1)^2
Length of data:
16 items

On 8/13/10, Marc LeBrun <mlb at well.com> wrote:
>>="N. J. A. Sloane" <njas at research.att.com>
>
>>> Can superseeker be used to look for formulas for an existing sequence,
>>> rather
>>> than just reporting that the sequence already exists?
>>
>> Yes, it does that automatically. If the sequence is
>> in the OEIS it tells you; independently, if it
>> finds a formula it tells you that too
>>
>> (I think! Haven't looked at the source code for years)
>>
>
> ========
>
> Easier to just try it!  Using the "odd numbers" example at
> http://www.research.att.com/~njas/sequences/ol.html
> I do get the [much snipped] output further below.
>
> Some comments:
>
>   *  Perhaps the above page should emphasize "...it will ALSO apply a large
> number of algorithms..."?
>
>   *  Does it try ALL the algorithms?  I would have expected that many
> transforms of the odd numbers would be in the OEIS. (This exemplifies why
> systematically augmenting the OEIS with at least the main transforms of the
> 169 core sequences seems a worthwhile priority).
>
>   *  Also, a longstanding feature request: have Superseeker parrot back
> whatever is in the Subject line of the query as the Subject of its reply, to
> make them easier to manage in eMail folders.
>
>   *  A while back some seqfans looked into specifying an XML schema for OEIS
> entries, as an alternative to the classic "human readable" format.  It would
> be relatively trivial to convert between them, and would enable then folks
> to implement custom renderings, web services (eg other seekers) etc.  Maybe
> this would be more timely to pursue nowadays?
>
> --------
>
> Report on [ 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31]:
> Many tests are carried out, but only potentially useful information
> (if any) is reported here.
>
>
> TEST: IS THE SEQUENCE OF ABSOLUTE VALUES IN THE ENCYCLOPEDIA?
> Matches (up to a limit of 50) found for
> "1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31"
>
> %I A005408 M2400
> ...
>
> %I A006257 M2216
> ...
> %I A176271
> ...
> %I A060747
> ...
> %I A004273
> ...
> %I A113648
> ...
> %I A053229
> ...
> %I A089684
> ...
> %I A033041
> ...
> %I A105356
> ...
> %I A109846
> ...
> %I A172049
> ...
> %I A157142
> ...
> %I A165747
> ...
>
>         SUCCESS: the sequence is in the OEIS.
>
>
> TEST: IS THE NTH TERM A POLYNOMIAL IN N?
>         SUCCESS: nth term is nontrivial polynomial in n of
> degree 1
> Polynomial is:
> 1+2*n
> memory used=1.4MB, alloc=1.7MB, time=0.01
>
> Sequence is a polynomial of degree at most 2.  Bye!
>
> ...
>
>
>
>
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>
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>




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