[seqfan] Re: Permutations with 2K-2 odd displacements, formula?
rhhardin at att.net
Sun Jun 2 13:16:20 CEST 2013
Sorry, the proof is nonsense. Something like the proof is right.
rhhardin at mindspring.com
rhhardin at att.net (either)
----- Original Message ----
> From: Ron Hardin <rhhardin at att.net>
> To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> Sent: Sun, June 2, 2013 7:05:24 AM
> Subject: [seqfan] Re: Permutations with 2K-2 odd displacements, formula?
> I suppose it's easy to prove, given the answer
> Define a permutation by four choosings:
> Order the even elements (factorial((n+1)/2))
> Order the odd elements (factorial(n/2))
> The first k-1 even elements go to the first k-1 odd elements in all ways
> The first k-1 odd elements go to the first k-1 even elements in all ways
> The remaining even elements appear in unfilled even slots in their new order
> The remaining odd elements appear in unfilled odd slots in their new order
> Assuming this is right, the word empirical can be dropped and the formula gets
> promoted to the title, and the problem to a comment.
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