[seqfan] Pebble Transform and prime numbers

Eric Angelini Eric.Angelini at kntv.be
Thu Nov 19 16:48:17 CET 2009

We could play the same game with the digits inside an integer...

Let's define the "Pebble Transform" (PT) like this:

Start with an integer (say '34102')
Define 'd' as the number of non-zero digits (here d=4)
Make every digit minus 1, except for the zero digits (34102
                                                  --> 23001)
Write 'd' ahead of the result (423001)

... and now iterate the PT until:
- the resulting integer has more zeros at the end than the one which
  was used for the first PT;
- the resulting integer is a prime


[Tanya K.]
> You have 45 pebbles arranged in several piles. Each turn you take one 
> pebble from each pile and put them into a new pile. 
> For example, if you start with one pile of 6, next step will be two 
> piles: {1,5}, then {2,4} and so on. Eventually the sequence of partitions 
> will start repeating itself.

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