A174083 Number of circular permutations of length n with no consecutive triples (i, i+d, i+2d) (mod n) for all d.

4, 0, 40, 168, 1652, 9408, 117896, 1019260, 12737856, 140794368, 2072921376, 25990014896, 439692361160

Offset: 4

Author

Isaac Lambert, Mar 15 2010

Keywords

• nonn
• more

Comments

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

Examples

			For n=5 since a(5)=0 all (5-1)! = 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

Cf. A165962, A174075, A174080, A174081, A174082.

Extensions

a(10)-a(13) from Andrey Goder, Jul 03 2022

a(14)-a(16) from Bert Dobbelaere, May 18 2025