Number of paths joining opposite corners of an n X 4 grid with every vertex appearing at most twice in the path.

A247106

Number of paths joining opposite corners of an n X 4 grid with every vertex appearing at most twice in the path.

Terms

    a(0) =5a(1) =2100a(2) =457712a(3) =112269228a(4) =28477328812

External references