[seqfan] Re: A269526, an infinite Sudoku-type array

[israel at math.ubc.ca]

Of course there are permutations of order 4. For example, a(4k)=4k-3, 
otherwise a(n)=n+1:

2, 3, 4, 1, 6, 7, 8, 5, 10, 11, 12, 9, 14, 15, 16, 13, 18, 19, 20, 17, 22, 
23, 24, 21, 26, 27, 28, 25, 30, 31

Hmm, that seems to match a shift of A109680 without the first term, at 
least for the given Data.

Cheers,
Robert


On Jun 30 2016, Paul D Hanna wrote:

>Nice observation, Don. 
>   
> I think it is interesting that, if a(n) = A065189(n), then the following 
> 'almost' holds:
>  
>     a(a(a(a(n)))) = n 
>   
> That causes me to wonder if someone knows of a non-trivial example of 
> such a sequence.
> 
> Question: Is there a non-trivial permutation of the natural numbers a(n) 
> such that a(a(n)) results in a self-inverse permutation?
> 
>Surely there are several examples of such a sequence in the OEIS ...     
>
>---------- Original Message ----------
>From: Don Reble <djr at nk.ca>
>To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
>Subject: [seqfan] Re: A269526, an infinite Sudoku-type array
>Date: Thu, 30 Jun 2016 00:10:13 -0600
>
>
>> There are a lot of other related sequences, for example, in row n, where
>> does 1 appear?
>
>    A065189. See also A065188.
>
>