A174077 Number of permutations of length n with no consecutive triples i,i+2,i+4 (mod n) or i,i-2,i-4 (mod n).

1, 1, 2, 0, 24, 80, 504, 3794, 31616, 290970, 2973600, 33311520, 405781344, 5342413414, 75612197528, 1144942063230, 18471128518656, 316309310084728, 5730646943736936

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Example

As an example, (0,4,1,2,3) is counted by a(5), but (0,4,1,3,2) is not because it has the progression 4,1,3.

Crossrefs

Cf. A165963, A174076, A174078, A174079.

Sequence in context: A130915 A356576 A127067 * A365980 A052607 A052602

Adjacent sequences: A174074 A174075 A174076 * A174078 A174079 A174080

Keyword

nonn,more

Author

Isaac Lambert, Mar 10 2010

Extensions

Definition corrected by Isaac Lambert, Mar 15 2010

a(0)-a(4) and a(10)-a(18) from Alois P. Heinz, Apr 15 2021

Status

approved