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Number of circular permutations of length n with no consecutive triples (i, i+d, i+2d) (mod n) for all d.
3

%I #14 Jul 04 2022 01:35:23

%S 4,0,40,168,1652,9408,117896,1019260,12737856,140794368

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

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

%e 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.

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

%K nonn,more

%O 4,1

%A _Isaac Lambert_, Mar 15 2010

%E a(10)-a(13) from _Andrey Goder_, Jul 03 2022