[seqfan] Re: 10 different digits, 9 products

[Maximilian Hasler]

Hello Eric,

I have created the sequence http://oeis.org/A203569 :
Numbers whose digits are a permutation of [0,...,n] and which contain
the product of any two adjacent digits as a substring.

which generalizes the problem to a smaller number of digits.

I found it interesting that considering permutations of [1,...,n]
instead yields only three nontrivial solutions,
3412, 4312 and 71532486
(plus the trivial solutions 1, 12, 21, 213, 312).

Best wishes,

Maximilian

On Tue, Jan 3, 2012 at 8:08 AM, Eric Angelini <Eric.Angelini at kntv.be> wrote:
>
> Hello SeqFans,
> I'm looking for all T numbers with 10 digits (digits must be
> different one from another) having this property :
> when you multiply two touching digits of D, the result is
> visible in D (as a character string).
> Example:
> 9071532486 --> the product 9*0 is in T ("0"); the product 0*7
> is in T too ("0"); 7*1 ("7"); 1*5 ("5"); 5*3 ("15"); 3*2 ("6");
>  2*4 ("8"); 4*8 ("32") et 8*6 ("48").
> I have also 4297631805 (4*2="8"; 2*9="18"; 9*7="63"; 7*6="42";
> 6*3="18"; etc.)
> The same for 5420976318, 7963205418, 5630187924, 5678142309, ...
> This has a flavour of Zak's http://oeis.org/A134962
> Best,
> É.
>
>
>
>
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