

A174083


Number of circular permutations of length n with no consecutive triples (i, i+d, i+2d) (mod n) for all d.


3




OFFSET

4,1


COMMENTS

Circular permutations are permutations whose indices are from the ring of integers modulo n.


LINKS



EXAMPLE

For n=5 since a(5)=0 all (51)! = 24 circular permutations of length 5 have some consecutive triple (i, i+d, i+2d) (mod 5). For example, the permutation (0,4,2,1,3) has a triple (1,3,0) with d=2. This is clearly a special case.


CROSSREFS



KEYWORD

nonn,more


AUTHOR



EXTENSIONS



STATUS

approved



