A078673 Number of ways of arranging the numbers 1..n in a circle so that there is no consecutive triple i, i+1, i+2 or i, i-1, i-2 (mod n).

1, 1, 0, 2, 6, 38, 247, 1831, 15287, 142199, 1459462, 16395802, 200200031, 2640841839, 37433428955, 567531704959, 9165263237530, 157084952558930, 2847992358978623, 54460529906884855, 1095499061960126311, 23125162555673245847, 511150714875199094358

Offset: 1

Author

N. J. A. Sloane, Dec 16 2002

Keywords

• nonn

Comments

Arrangement that differ only in the direction in which the cycle is traversed do not count as different.

Links

• Index entries for sequences related to shoe lacings

Crossrefs

Apart from initial terms, A078628/2.

Extensions

More terms from Sean A. Irvine, Jul 10 2025