[seqfan, OEIS-ideas] More sequence show-script ideas.

Antti Karttunen Antti.Karttunen at iki.fi
Wed Jun 11 20:00:39 CEST 2003



Frank Ellermann wrote:
> 
> P.S.: But I refuse to patch each and every subject only to keep
>       _your_ inbound sorted by some obscure (for me) criteria

No, I wasn't forcing everybody to do the same... ;-)


But, yes, more formats are good for showtabl.c

However, I'm thinking also about something like
"a semi-intelligent sequence-plotter", i.e. from the
page generated by Sequence-link we could have
a Java-applet instantiated with the sequence terms
(and the keywords), and it would then plot the graph
of the sequence (interpreted as a "n -> f(n) function"),
automatically choicing an appropriate logarithmic
scale, depending on the growth rate of the sequence.
(Note that many EIS sequences exceed the 2^64 - 1 limit
of Java integers, so something like bignums would be necessary,
or a blunt error message, like "terms 7-9 of this sequence
could not be processed because too huge...")

Maybe one could also have a choice of toggling between different
logarithmic / straight scales in the Java applet display,
and also have a simple "star-plot", like:

*                                                               
 *                                                              
   *                                                            
  *                                                             
       *                                                        
      *                                                         
    *                                                           
     *                                                          
               *                                                
              *                                                 
            *                                                   
             *                                                  
        *                                                       
         *                                                      
           *                                                    
          *                                                     
                               *                                
                              *                                 
                            *                                   
                             *                                  
                        *                                       
                         *                                      
                           *                                    
                          *                                     
                *                                               
                 *                                              
                   *                                            
                  *                                             
                       *                                        
                      *                                         
                    *                                           
                     *                                          
                                                               *
                                                              * 
                                                            *   
                                                             *  
                                                        *       
                                                         *      
                                                           *    
                                                          *     
                                                *               
                                                 *              
                                                   *            
                                                  *             
                                                       *        
                                                      *         
                                                    *           
                                                     *          
                                *                               
                                 *                              
                                   *                            
                                  *                             
                                       *                        
                                      *                         
                                    *                           
                                     *                          
                                               *                
                                              *                 
                                            *                   
                                             *                  
                                        *                       
                                         *                      
                                           *                    
                                          *                     
 

which would be a nice feature for many "permutation of N" sequences.
(This example from from Wouter Meeussen's "Sun, 25 May 2003 18:13:51 +0200"
SeqFan-mail, "Re: fractal sequences",
for the sequence http://purl.net/net/eisa/A066194 )

I personally hate coding Java, but I could ask from sci.math
or similar newsgroup, whether anything like that has been coded
in Java or C and is available as open source,
or whether any volunteer would like to WRITE one from a scratch!

Other alternative would be to generate the plots  and displays
like above at the OEIS side (e.g. using Boutell's on-the-fly
GIF-or-PNG drawing library), but I think that puts too much
burden there.


Yours,

Antti





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