[seqfan] Re: Strings resurrection

[Giovanni Resta]

On 09/08/2012 04:17 PM, Eric Angelini wrote:
>
> Hello SeqFans,
> Start with n = 127. Replace, one by one, every digit 'd' of n by 'd+1'. Iterate.
> 127 ->  238 ->  349 ->  4510 ->  5621 ->  6732...
> Questions:
> *Will the substring<127>  reappear at some stage in the iteration of 127?

No, it will not reappear.

In general, a 0 can only come from a 9, and thus
it must always have a 1 in front of it.
In other words it is impossible to have the substring ..x0..
unless x=1.

So ..127.. comes from  ..016.. which must be ..1016..
which comes from ..905.. which is impossible to obtain,
since we have the impossible 90.

giovanni resta