[seqfan] Re: Most efficient way to construct a list of pandigital palindromic numbers?
Alonso Del Arte
alonso.delarte at gmail.com
Mon Dec 7 23:44:05 CET 2009
Come to think of it, no, I don't need to have all possible permutations
available together. In fact, just the palindromic pandigital numbers
starting with 1 (and obviously ending with 1) would probably be more than
enough for my purpose, which is to verify the validity of
A168334<http://www.research.att.com/~njas/sequences/A168334> and
perhaps add another four or eight terms.
Al
On Mon, Dec 7, 2009 at 5:34 PM, William Keith <wjk26 at drexel.edu> wrote:
>
> On Dec 7, 2009, at 5:16 PM, Alonso Del Arte wrote:
>
> > In Mathematica, what is the most efficient way to build a list a
> > pandigital
> > palindromic numbers? Even with Mathematica as the only program
> > running, the
> > command Permutations[{0,1,2,3,4,5,6,7,8,9}] causes Mathematica to shut
> > down
> > the kernel and suggest I quit more programs.
> >
> > Al
>
> Sounds like memory overflow. Does whatever you're attempting to do
> with your numbers require that you have all 3.6 million permutations
> available at once, or can you construct your permutations on the fly
> when you need to count or check something? Could you loop through the
> 45 lists of eight of the possible digits, and use the permutations of
> these (a much smaller chunk) headed with the two remaining digits in
> each order?
>
> William Keith
>
>
>
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