A174081 Number of permutations of length n with no consecutive triples i,i+d,i+2d (mod n) for all d.

16, 40, 300, 1764, 17056, 118908

Offset

4,1

Links

Table of n, a(n) for n=4..9.

Example

For n=4, there are 4!-a(4)=8 permutations with some consecutive triple i,i+d,i+2d (mod 4). Here only d=1 and d=3 works, and the permutations are (0,1,2,3), (1,2,3,0), (2,3,0,1), (3,0,1,2), (0,3,2,1), (3,2,1,0), (2,1,0,3), and (1,0,3,2)

Crossrefs

Cf. A095816, A174073, A174080, A174082, A174083.

Sequence in context: A197903 A300901 A174086 * A230802 A100958 A246344

Adjacent sequences: A174078 A174079 A174080 * A174082 A174083 A174084

Keyword

nonn

Author

Isaac Lambert, Mar 15 2010

Status

approved