Number of paths through the subset array of {1,2,...,n} that have range a subset of {1,2}; see Comments at A208650.
A208661
Number of paths through the subset array of {1,2,...,n} that have range a subset of {1,2}; see Comments at A208650.
Terms
- a(0) =1a(1) =4a(2) =16a(3) =144a(4) =3072a(5) =160000a(6) =20736000a(7) =6776582400
External references
- oeis: A208661