A078674 Number of ways to lace a shoe that has n pairs of eyelets, assuming the lacing satisfies certain conditions.

1, 3, 50, 2122, 155712, 17441962

Offset: 1

Author

N. J. A. Sloane, Dec 16 2002

Keywords

• nonn

Comments

The lace must follow a Hamiltonian path through the 2n eyelets and cannot pass in order though three adjacent eyelets that are in a line.

The lace is "undirected": reversing the order of eyelets along the path does not count as a different solution (cf. A078629).

Links

• Index entries for sequences related to shoe lacings

Crossrefs

Apart from initial term, A078629/2.