Number of ways to lace a shoe with n eyelet pairs such that there is no direct "horizontal" connection between any adjacent eyelet pair.
A072503
Number of ways to lace a shoe with n eyelet pairs such that there is no direct "horizontal" connection between any adjacent eyelet pair.
Terms
- a(0) =3a(1) =45a(2) =1824a(3) =109560a(4) =9520560a(5) =1145057760a(6) =181091917440
External references
- oeis: A072503