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Re: Arrangements

On 06.04.2010 13:23, John wrote:
> Google 6, Windows-Xp
> The number of different arrangements of sixteen symbols -- eight
> letters A and eight letters B -- is Binomial[16,8]=12870. Is there a
> command that will generate all 12870 arrangements one at a time
> without duplication? Any order is acceptable.
> I used RandomSample[Range[16]] to select a random permutation of
> sixteen different symbols. Assigning the letter A to the first eight
> numbers in the random permutation and the letter B to the last eight
> letters in the permutation created a randomly selected arrangement.
> Awkward, but it works because Binomial[2n,n](n!)(n!)=(2n)!).
> John
Hi John,
you may create all arrangements in one go by:
Needs ["Combinatorica`"];
t = DistinctPermutations[Join[Table["a", {8}], Table["b", {8}]]];
cheers, Daniel


Daniel Huber
Metrohm Ltd.
Oberdorfstr. 68
CH-9100 Herisau
Tel. +41 71 353 8585, Fax +41 71 353 8907
E-Mail:<mailto:dh at>

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