Number of paths joining opposite corners of an n X 3 grid with every vertex appearing at most twice in the path.
A247070
Number of paths joining opposite corners of an n X 3 grid with every vertex appearing at most twice in the path.
Terms
- a(0) =3a(1) =218a(2) =9482a(3) =457712a(4) =22375458a(5) =1103498043a(6) =54446999831
External references
- oeis: A247070