[seqfan] Re: Permutations whose sum mod n is also a permutation

[Ron Hardin]

> 
> 1,0,12,0,960,0,337680,0,367597440
> Number  of lexicographically ordered pairs of permutations of 0..(n-1) such 
>that 
>
> their sum mod n is also a permutation of 0..(n-1)

Simplifying the problem a little:

1,0,3,0,15,0,133,0,2025,0,37851,0,1030367
Number of permutations p(i) i=0..(n-1) of 0..(n-1) such that (p(i)+i) mod n is 
also a permutation of 0..(n-1)

gives  
http://www.research.att.com/~njas/sequences/A006717