Almost-convex polygons of perimeter 2n on square lattice.

A007220

Almost-convex polygons of perimeter 2n on square lattice.

Terms

    a(0) =4a(1) =60a(2) =588a(3) =4636a(4) =31932a(5) =200364a(6) =1174492a(7) =6538492a(8) =34965772a(9) =181084796a(10) =913687100a(11) =4511834156a(12) =21880671292a(13) =104497300828a(14) =492527133804

External references