Number of paths joining opposite corners of an n X 2 grid with every vertex appearing at most twice in the path.
A239688
Number of paths joining opposite corners of an n X 2 grid with every vertex appearing at most twice in the path.
Terms
- a(0) =2a(1) =22a(2) =218a(3) =2100a(4) =20701a(5) =202664a(6) =1990006a(7) =19519656a(8) =191538146a(9) =1879225062a(10) =18438413081a(11) =180909222618
External references
- oeis: A239688